John Glenn, who captured the nation’s attention in 1962 as the first American to orbit the Earth during a tense time when the United States sought supremacy over the Soviet Union in the space race, and who rocketed back into space 36 years later, becoming the oldest astronaut in history, died Dec. 8 at a hospital in Columbus, Ohio. Mr. Glenn, who in his post-NASA career served four terms as a U.S. senator from Ohio, was 95.

The death was confirmed by Hank Wilson, communications director at the John Glenn College of Public Affairs at Ohio State University. Mr. Glenn had a stroke after heart-valve replacement surgery in 2014, but the immediate cause was not announced.

Mr. Glenn was one of the seven original astronauts in NASA’s Mercury program, which was a conspicuous symbol of the country’s military and technological might at the height of the Cold War. He was not the first American in space — two of his fellow astronauts preceded him — but his three-orbit circumnavigation of the globe captured the imagination of his compatriots like few events before or since. Mr. Glenn was the last survivor of the Mercury Seven.

“John always had the right stuff,” President Obama said in a statement, adding that Mr. Glenn “reminded us that with courage and a spirit of discovery there’s no limit to the heights we can reach together.”

In an era when fear of encroaching Soviet influence reached from the White House to kindergarten classrooms, Mr. Glenn, in his silver astronaut suit, lifted the hopes of a nation on his shining shoulders. When he emerged smiling from his Friendship 7 capsule after returning from space, cheers echoed throughout the land.

John Glenn, the first American to orbit the earth and the oldest man in space, has died at 95. (Thomas Johnson/The Washington Post)

“You had to have been alive at that time to comprehend the reaction of the nation, practically all of it,” author Tom Wolfe, who coined the phrase “the right stuff” to describe Mr. Glenn and the other Mercury astronauts, wrote in a 2009 essay. “John Glenn, in 1962, was the last true national hero America has ever had.”

After he was elected to the U.S. Senate from Ohio in 1974, Mr. Glenn served on Capitol Hill for 24 years and made a halfhearted run for the Democratic presidential nomination in 1984. When he was 77 and completing his fourth Senate term in 1998, he had one final flight of glory, returning to space as a crew member aboard the space shuttle Discovery.

As heroes go, the freckle-faced Mr. Glenn appeared unassuming and seemed to embody the middle-American values of modesty, steadiness and hard work.

He had climbed the ranks of the Marine Corps by accepting the most dangerous assignments and never flinching under pressure. He flew 149 combat missions in two wars and was a test pilot in the 1950s, when faster-than-sound airplanes often veered out of control and crashed in smoking heaps.

When he joined the astronaut corps in 1959, no one knew whether a human being could survive the ordeals of space travel. Yet for all the risks he faced, Mr. Glenn was a man of careful preparation and quiet responsibility.

In this clip from a 1962 NASA documentary, John Glenn launches into space aboard the Friendship 7 on the first orbital flight by an American astronaut. (NASA)
‘Godspeed, John Glenn’

On Oct. 4, 1957, the Soviet Union made a bold advance on the Cold War chessboard by launching Sputnik, the first man-made satellite to orbit Earth. In response, the U.S. government formed NASA in 1958 amid widespread fear that the country was falling behind the Soviets in technology and military strength.

Of the seven original astronauts of the Mercury program — the others were M. Scott Carpenter, L. Gordon Cooper Jr., Virgil I. “Gus” Grissom, Walter M. “Wally” Schirra Jr., Alan B. Shepard Jr. and Donald K. “Deke” Slayton — Mr. Glenn was the oldest and the lone Marine. A lieutenant colonel at the time — who ultimately became a full colonel — he also had the highest rank and the most combat experience.

He did not drink, smoke or swear and maintained a disciplined, straight-arrow manner while training in Cocoa Beach, Fla., near NASA’s space center at Cape Canaveral. Comfortable in front of cameras — which followed the astronauts everywhere after they signed a $500,000 deal with Life magazine for a series of exclusive stories — Mr. Glenn was in many ways the public face of NASA.

Privately, however, there was friction among the “Magnificent Seven,” as the Mercury astronauts were dubbed in the news media. Concerned that some of his colleagues’ dalliances with women could lead to bad publicity and jeopardize the manned space program, Mr. Glenn confronted his fellow astronauts, admonishing them to avoid any semblance of wrongdoing.

“There was no doubt whatsoever that Glenn meant every word of it,” Wolfe wrote in his 1979 book, “The Right Stuff.” “When he got his back up, he was formidable. He was not to be trifled with.”

Not all of the astronauts were pleased with Mr. Glenn’s righteousness, however, and Shepard told him to mind his own business.

“His moralizing led to colorful and heated exchanges among the pilots, and it wasn’t pleasant banter,” Shepard and Slayton wrote in their 1995 book, “Moon Shot.”

When the astronauts voted among themselves to confer the honor of being the first American in space, they chose Shepard.

On May 5, 1961, Shepard had a 15-minute suborbital space flight, followed two months later by Grissom on a similar mission. But two Soviet cosmonauts had already circled the Earth by August 1961.

Mr. Glenn’s turn came on Feb. 20, 1962. After 11 delays because of bad weather or faulty equipment, he sat in his tiny space capsule, the Friendship 7, atop an MA-6 rocket that had failed in 40 percent of its test flights.

After liftoff at 9:47 a.m., backup pilot Carpenter said on an internal tape later released to the public, “Godspeed, John Glenn.”

The moment was shared by practically the entire nation, as a television audience of 135 million — the largest up to that time — witnessed the launch.

After the first of three scheduled orbits, the capsule began to wobble. Mr. Glenn overrode the automatic navigation system and piloted Friendship 7 with manual controls, reaching a height of 162 miles above the Earth’s surface.

Midway through the flight, a warning light indicated that the heat shield, which would protect the capsule during its reentry into Earth’s atmosphere, might have come loose. Without a heat shield, it was possible that Mr. Glenn could burn up inside the capsule as it raced back from space.

As Friendship 7 was descending, all radio contact was lost. Shepard, acting as “capsule communicator” from Cape Canaveral, tried to reach Mr. Glenn in his spacecraft, saying, “How do you read? Over.”

After about 4 minutes and 20 seconds of silence, Mr. Glenn could finally be heard: “Loud and clear. How me?”

“How are you doing?” Shepard asked.

“Oh, pretty good,” Mr. Glenn casually responded, later adding, “but that was a real fireball, boy.”

Exterior pieces of the capsule’s had broken off during reentry and burst into flame. A defective warning light caused much of the panic, but during those four tense minutes, it was feared that Mr. Glenn had been lost — along with the promise of the space program.

When he splashed down in the Atlantic Ocean after 4 hours 56 minutes aloft, Mr. Glenn emerged as an almost mythic figure who had scaled heights no American had reached before.

“I was fully aware of the danger,” he said in 1968. “No matter what preparation you make, there comes the moment of truth. You're playing with big stakes — your life. But the important thing to me wasn’t fear but what you can do to control it.”

He was greeted upon his return by President John F. Kennedy and Vice President Lyndon B. Johnson. After an estimated 1 million spectators crowded the streets of Washington, Mr. Glenn insisted that the other six Mercury astronauts join him for a parade before 4 million people in New York.

“During his ticker-tape parade up Broadway,” Wolfe wrote, “you have never heard such cheers or seen so many thousands of people crying.”

From pilot to politics

John Herschel Glenn Jr. was born July 18, 1921, in Cambridge, Ohio, and grew up in New Concord, Ohio. His father ran a plumbing supply business and later had a Chevrolet dealership. His mother taught at an elementary school.

Mr. Glenn was an honor student in high school, lettered in three sports and played trumpet in the band. At Muskingum College in New Concord, he was a reserve center on the football team.

He took flying lessons in his teens and left college early in 1942 to enter a Navy pilot training program before transferring to the aviation branch of the Marine Corps. On April 6, 1943, he married Anna “Annie” Castor, whom he had known since childhood.

During World War II, Mr. Glenn flew 59 missions as a fighter pilot and took part in the Marshall Islands campaign in the Pacific. He was stationed on Guam in the Western Pacific and was a flight instructor in Texas before returning to action in the Korean War.

He was in the same squadron in Korea as baseball star Ted Williams and flew 90 missions as a jet fighter pilot. He once returned with more than 200 holes shot through the fuselage and wings of his plane.

Attached to an Air Force unit, Mr. Glenn shot down three Soviet-made MiGs during the final nine days of the war in 1953, leading his crew to paint “MiG Mad Marine” on the side of his F-86 Sabre jet.

After Korea, Mr. Glenn was a test pilot at the naval air station at Patuxent River, Md., and set a transcontinental speed record on July 16, 1957, by flying an F8U-1 Crusader jet coast to coast in 3 hours 23 minutes.

He worked at the Navy’s Bureau of Aeronautics and eventually was awarded a bachelor’s degree by Muskingum. He also found time in 1957 to appear on the game show “Name That Tune” with child actor Eddie Hodges. They split $25,000 in prize money, which was more than Mr. Glenn’s annual pay as a test pilot.

When NASA began recruiting a team of astronauts, it sought skilled pilots who could withstand rigorous physical and psychological testing and who — to fit into cramped space capsules — were shorter than 5 feet 11 inches tall. (Mr. Glenn was 5-foot-101 / 2.)

With their courage and know-how, the Mercury astronauts embodied the spirit of the “New Frontier” espoused by Kennedy, and Mr. Glenn became friends with the youthful president and his brother Robert F. Kennedy, the attorney general.

Encouraged by the Kennedy family, Mr. Glenn resigned from the astronaut corps in 1964 to run for the U.S. Senate in Ohio. He dropped out after slipping on a rug and striking his head on a bathtub, resulting in inner-ear problems that required extensive medical treatment. In 1965, he retired from the Marine Corps, having received six Distinguished Flying Crosses and 19 Air Medals.

He then became an executive with Royal Crown Cola, invested in real estate and worked with a management company that operated Holiday Inns, particularly around Orlando. Within a few years, he was a millionaire.

Mr. Glenn stayed close to the Kennedys and was at the Ambassador Hotel in Los Angeles when Robert Kennedy was assassinated in June 1968. He accompanied five of Kennedy’s 10 children (an 11th was born after his death) back to their home in McLean, Va. The next morning, Mr. Glenn informed the other children that their father had been killed.

“When Bob died, I had to sit on the edge of the bed as each child was waking up and tell them their dad was not coming home,” Mr. Glenn told a Muskingum audience in 1997. “It was one of the hardest things I ever did.”

He was a pallbearer at Robert Kennedy’s funeral at Arlington National Cemetery and handed the flag from the coffin to Sen. Edward M. Kennedy (D-Mass.). Soon afterward, Mr. Glenn helped organize a group that successfully lobbied for passage of a national gun control act in 1968.

‘I have held a job, Howard’

Making a second bid for the Senate in 1970, Mr. Glenn called for the withdrawal of U.S. troops from Vietnam, but he lost the Democratic primary in Ohio to businessman Howard M. Metzenbaum. Then-Rep. Robert Taft Jr., a Republican, won the general election.

Early in 1974, Metzenbaum was appointed to the Senate to fill the expiring term of William B. Saxbe, who resigned to become U.S. attorney general. When Metzenbaum ran for a full Senate term that year, Mr. Glenn challenged him again in the primary.

At a time when the military was unpopular, Metzenbaum repeatedly called Mr. Glenn “colonel” and questioned his ability as a leader, saying he had never “met a payroll.” The comment was widely seen as an insult, insinuating that Mr. Glenn had never held a “real” job.

In a debate with Metzenbaum, the retired Marine flashed the steel beneath his benign Midwestern smile.

“I served 23 years in the United States Marine Corps,” Mr. Glenn said. “I was through two wars. I flew 149 missions. My plane was hit by antiaircraft fire on 12 different occasions.

“I was in the space program. It wasn’t my checkbook, it was my life that was on the line. . . . I ask you to go with me . . . to a veterans hospital, and look those men with their mangled bodies in the eye and tell them they didn’t hold a job.

“You go with me to any Gold Star mother, and you look her in the eye and tell her that her son did not hold a job.

. . . Stand in Arlington National Cemetery — where I have more friends than I like to remember — and you watch those waving flags . . . and you tell me that those people didn’t have a job.

“I tell you, Howard Metzenbaum, you should be on your knees every day of your life thanking God that there were some men — some men — who held a job. . . . And their self-sacrifice is what has made this country possible.

“I have held a job, Howard.”

The powerful “Gold Star Mother” speech, recognizing families that had lost children in foreign wars, quickly turned the polls in Mr. Glenn’s favor. He defeated Metzenbaum in the primary and then easily won the November general election, sweeping all of Ohio’s 88 counties. Reelected in 1980, 1986 and 1992, Mr. Glenn was the first senator from Ohio to win four consecutive elections.

A senator in space

On Capitol Hill, Mr. Glenn was a strong supporter of the military and an authority on intelligence issues. He supported a woman’s right to abortion and was an advocate of campaign finance reform, national health insurance and medical research.

He sponsored bills to improve the safety of nursing homes, reduce government paperwork and limit nuclear proliferation. As chairman of the Governmental Affairs Committee from 1988 to 1994, he helped create the Department of Veterans Affairs.

In the late 1980s, Mr. Glenn’s political action committee accepted a contribution from financier Charles H. Keating Jr., who was at the center of a nationwide savings-and-loan scandal. The Senate Ethics Committee ruled that Mr. Glenn “exercised poor judgment,” but he was cleared of any wrongdoing.

He made a run for the 1984 Democratic presidential nomination but proved to be an awkward campaigner and quit the race early, saying, “I humiliated my family, gained 16 pounds and went millions of dollars into debt.”

On Feb. 20, 1997, the 35th anniversary of his spaceflight, Mr. Glenn announced that he would not run for reelection in 1998. He established a public policy institute at Ohio State University and wrote his memoirs. In 2012, Mr. Glenn was awarded the Presidential Medal of Freedom, the nation’s highest civilian honor.

In addition to his wife, of Columbus and Bethesda, Md., survivors include two children, J. David Glenn of Berkeley, Calif., and Carolyn “Lyn” Glenn of St. Paul, Minn.; and two grandsons.

Revered for his heroism as an astronaut, Mr. Glenn remained close to the space program long after leaving NASA. In 1986, immediately after the explosion of the space shuttle Challenger, he made a little-publicized trip to Cape Canaveral to comfort the families of astronauts killed in the disaster.

Every year, he sent the results of his physical exams to NASA, just in case. At 75, he could still do 75 push-ups. In 1996, he set a flying record by piloting a twin-engine plane from Dayton, Ohio, to Washington in 1 hour, 36 minutes.

When Mr. Glenn was named to the crew of the space shuttle Discovery, skeptics said NASA was awarding him a vanity flight to make him, at 77, the oldest person ever to go into space. During the nine-day mission in 1998, Mr. Glenn helped film the flight and took part in experiments on aging. He made one of his final public appearances in June 2016, when the Columbus airport was renamed in his honor.

His return to space was a reminder of what he had accomplished more than three decades earlier, when he soared into the heavens and gave renewed hope to a grateful nation.

“People are afraid of the future, of the unknown,” he said in 1962. “If a man faces up to it and takes the dare of the future, he can have some control over his destiny.”