At a stocky 5 feet 11 and 210 pounds, Mr. Killebrew had a compact swing that produced some of the longest home runs of his era.
In 1962, he became the first right-handed hitter to slug a ball over the left-field roof of Tiger Stadium in Detroit, 94 feet above the playing field. On June 3, 1967, one of his home runs shattered two seats in the upper deck of Metropolitan Stadium in Bloomington, Minn. The seats, more than 520 feet from home plate, were painted orange as a lasting symbol of Mr. Killebrew’s prowess.
Paul Richards, a former manager of the Baltimore Orioles, once said, “Killebrew can knock the ball out of any park, including Yellowstone.”
Mr. Killebrew, who had the distinction of being the only Washington Senator discovered by a U.S. senator, made his big-league debut in 1954, six days before his 18th birthday. He catapulted to fame as the Senators’ third baseman in a 17-day period in May 1959 — he hit two home runs in each of five games.
He was named to the All-Star team in 1959 and, by season’s end, had belted 42 home runs, sharing the American League home-run title with Rocky Colavito of the Cleveland Indians.
After the 1960 season, the Senators left Washington and became the Minnesota Twins, and Mr. Killebrew burnished his legend as one of the greatest power hitters of all time. His 393 home runs from 1960 through 1969 were more than any other big-league player that decade.
During his career, he led the American League in home runs six times and in runs batted in (RBI) three times. He was named the league’s most valuable player in 1969. His eight seasons of 40 or more home runs are tied for second in major league history, behind Babe Ruth’s 11 seasons.
Mr. Killebrew hit his first big-league home run at Washington’s Griffith Stadium on June 24, 1955, when he was 18. In a game against the Detroit Tigers, he often recalled, the opposing catcher, Frank House, said, “Kid, we’re going to throw you a fastball.”
Mr. Killebrew hit the ball 476 feet — by measure of the Senators’ public relations director — or almost 100 feet beyond the left-field fence.
“As I was coming around the bases,” Mr. Killebrew told Baseball Digest magazine in 2004, “I stepped on home plate and Frank House said, ‘Kid, that’s the last time we’re ever going to tell you what’s coming.’ ”
Harmon Clayton Killebrew Jr. was born June 29, 1936, in Payette, Idaho. His father was a college football star at West Virginia Wesleyan College.
The younger Mr. Killebrew worked on ranches in his youth and grew up 15 miles from Weiser, Idaho, where Washington Senator great Walter Johnson had pitched for a semipro team in 1906 and 1907.
Mr. Killebrew was an outstanding high school quarterback and had a scholarship offer to play football and baseball at the University of Oregon when U.S. Sen. Herman Welker (R-Idaho) recommended the 17-year-old to Clark Griffith, the Senators’ owner.
Griffith signed Mr. Killebrew with a $30,000 bonus in 1954. Because “bonus babies” were required to remain on the major league roster for two years, Mr. Killebrew rode the bench for the Senators until 1956, when he reported to the minor leagues for his baseball apprenticeship.
No one doubted Mr. Killebrew’s ability to hit the ball, but his fielding was often suspect. Throughout his career, he was shifted among third base, first base and the outfield.
He appeared in his only World Series in 1965, when the Twins lost to the Los Angeles Dodgers in seven games.
After suffering a ruptured hamstring and dislocated hip in the 1968 All-Star Game, Mr. Killebrew bounced back with his finest season, winning the 1969 MVP award with 49 home runs and 140 RBI.
He played his final season with the Kansas City Royals in 1975 and retired with 573 home runs — fifth-most in history at the time. He was named to 11 All-Star teams.
Despite a low career batting average of .256, Mr. Killebrew had an extraordinary ability to draw walks and led the American League four times in that little-appreciated category. His lifetime on-base percentage of .376 was higher than that of Hall of Fame .300 hitters Hank Aaron, George Brett and Paul Molitor.
Mr. Killebrew was known for his quiet amiability and was never ejected from a game in his 22-year career. He was voted into the National Baseball Hall of Fame in 1984, and his No. 3 uniform was retired by the Twins.
After his playing career, he was a baseball broadcaster and owned insurance and car businesses. In the late 1980s, he faced financial reversals that caused him to lose his home and declare bankruptcy. He invested hundreds of thousands of dollars with a California developer who was later convicted of fraud.
Mr. Killebrew’s first marriage, to the former Elaine Roberts, ended in divorce.
Survivors include his wife of 20 years, Nita Patten Killebrew; five children from his first marriage; four stepchildren; 23 grandchildren; and two great-grandchildren.
After the Senators left Washington, Mr. Killebrew was a strong advocate of returning baseball to the nation’s capital. He had fond memories of Washington, including a game in 1959, when President Dwight D. Eisenhower asked him to autograph a home run ball for his grandson, David Eisenhower.
“I told him I’d sign one for him if he’d sign one for me,” Mr. Killebrew told The Washington Post in 1975. “He did, and I still have it.”