For years, the most prominent figure at Texas Southern University was a slim, short-bearded debate coach known as Doc — a master of forensic speech, or the art of public speaking and debate, who outshined the university’s football coaches, outlasted 12 school presidents and built one of the country’s most celebrated debate programs.

A Baptist minister as well as a professor, Thomas F. Freeman was one of those rare instructors whose mentorship and guidance outside the classroom was prized as much as his teaching. His students included the Rev. Martin Luther King Jr., gospel singer Yolanda Adams and Rep. Barbara Jordan (D-Tex.), whose eloquent and impassioned speeches captivated national audiences in the 1970s.

“I cannot overestimate the impact and influence Dr. Freeman had on my life,” Jordan once told the New York Times. “He stretches your mind. He places you on your own, teaches you to stand on your feet, think, and open your mouth and talk.” Another former student, Texas state Sen. Rodney Ellis (D), told the newspaper: “He taught us to push as hard as we could to go as far as we could.”

At Texas Southern, a historically black university in Houston, Dr. Freeman was a campus fixture for more than seven decades, and a link to the Jim Crow era in which he and his debate teams struggled to find food and lodging on the road, even as they beat white competitors from Harvard and other elite institutions.

Dr. Freeman was 100 when he died June 6 at a hospital in Houston. His daughter, Carlotta Freeman, confirmed the death but did not give a precise cause and noted that he continued meeting with students until the campus closed in March because of the coronavirus pandemic.

Working 12 hours a day, six days a week — plus Sundays after church — Dr. Freeman taught philosophy, religion and speech classes; preached at Mount Horem Baptist Church in Houston’s Fifth Ward; and coached his championship debate team, which received hundreds of trophies and competed in cities including Paris and Berlin.

Dr. Freeman was so revered that when actor and filmmaker Denzel Washington began working on the 2007 movie “The Great Debaters,” about a winning all-black debate team in the 1930s, he tapped Dr. Freeman to lead a debate “boot camp” for the cast. The professor preached a philosophy of learning by doing and employed a mantra that served as his debate team’s motto: “What we do, we do well; what we don’t do well, we don’t do at all.”

Like some of his pupils, Dr. Freeman had once suffered from debilitating stage fright. He used breathing exercises to calm aspiring public speakers, although his voice — a strong baritone — also proved highly effective in coaxing students to the stage. “I don’t force them to get up there,” he told Texas Monthly in 2014, “but the request is so strongly stated that they dare not sit down.”

Dr. Freeman had little tolerance for mediocrity, excuses or speakers who failed to pronounce the word “often” with a silent “t.” Chewing gum was banned, and drinking from a water bottle was considered a rude interruption. At practices, he would sit in the audience with his legs crossed, stroking his beard in silence as he watched team members recite a speech by Sojourner Truth or a passage by novelist Toni Morrison, his former colleague at Texas Southern.

“Just when you thought it was perfect, he would say, ‘Again,’ ” said Kamau M. Marshall, who competed on Dr. Freeman’s debate teams in the late 2000s and is now director of strategic communications for Democrat Joe Biden’s presidential campaign. “You could think you had a flawless performance, and it was bad. He was a perfectionist.”

Dr. Freeman “taught old-school values,” said Leshelle V. Sargent, a Texas Southern debate veteran and publicity director at Warner Bros. Television. “He was all about shining a light on black excellence,” she added. “He was trying to show that you, too, even if you were black, could travel the world, speak well, receive an education.”

Such opportunities were far from a given when Dr. Freeman began coaching debaters in 1949. Over the next decade or so, he battled racism while traveling to competitions in the South, where, he once told the Houston Chronicle, he “suffered the humiliation of going into the back” of a segregated restaurant to feed Jordan and other hungry students on the road.

Lodging presented additional problems. When he and his team went to East Central State College in Oklahoma to compete in one of the region’s first integrated debate events, Dr. Freeman discovered there was no place that would take in his male students for the night.

“I looked in the phone book and found the name of a Baptist preacher,” he told the Times in 1992. “It was near midnight when I told him of our plight. He opened his doors and we slept on the floor.”

Dr. Freeman’s team went on to win a top prize at the event, which was followed by a celebratory dinner at which two of his students were invited to deliver speeches. In Dr. Freeman’s telling, their remarks were followed by an address from the host team’s coach, who declared: “Thirty years ago, I wrote a paper in which I argued that blacks were inherently inferior. After listening to the speeches tonight, I confess before this audience that I was wrong.”

“You could hear a pin drop,” Dr. Freeman later told the Times, adding that the episode was typical for his teams at that time. “It was a challenge,” he said. “They could have easily folded. They chose to go in another direction, to rise above it.”

The fourth of 15 children, Thomas Franklin Freeman was born in Richmond on June 27, 1919. His father was a wholesale produce merchant, and his mother was a homemaker; neither finished high school, but they ensured that advanced educations were an option for all 12 of their children who grew into adulthood.

As a boy, Thomas was so frail that a doctor told the family he wouldn’t live past age 7. But he gradually gained strength and, by age 9, had immersed himself in Scripture, delivering sermons while standing on a soapbox with a Bible in his hand.

It was an inauspicious beginning for a speech instructor. “He had such severe stage fright that when he would stand there reading, tears would pour from his eyes,” his daughter, Carlotta, said in a phone interview. “The women thought he had been struck by the Spirit — when in fact he was scared to death.”

By age 15, he had enrolled at Virginia Union University in Richmond, where he received a bachelor’s degree in English in 1939. Three years later he graduated from Andover Newton, a Massachusetts theological school now affiliated with Yale.

He was studying for his doctorate in homiletics, the art of preaching, when in 1947 he taught a religion course at Morehouse College in Atlanta. His students there included King, then a teenager studying sociology. Only years later, when Dr. Freeman traveled back to Georgia with his debate team, did he realize that the civil rights leader had been in his class.

“You don’t remember me,” King told him at a restaurant, extending his hand, “but I remember you. You taught me.”

Dr. Freeman, who received his PhD from the University of Chicago in 1948, said he was planning for a career in the ministry in Richmond when he accepted a short-term teaching offer from Texas Southern, then known as Texas State University for Negroes. But after organizing a debate for his philosophy class, he found himself helming the school debate team.

The team’s early success led university officials to implore Dr. Freeman to stay in Houston, where he remained on the Texas Southern faculty until formally retiring in 2013.

In addition to his teaching and debate work, Dr. Freeman served as dean of the college of arts and sciences and dean of the honors college, which now bears his name. He was also a lecturer in religion at Rice University, where in 1972 he became the first African American professor to teach in the humanities school.

Survivors include his wife of 67 years, the former Clarice Estell; three children, Carter, Carlotta and Thomas F. Freeman Jr.; a sister; six grandchildren; and two great-grandchildren.

“Life under God is what you make of it,” Dr. Freeman said at a party for his 99th birthday, where he vowed to continue working for as long as his health permitted. “If you don’t bring anything to life, you won’t get anything out of it. You’re not here for your enjoyment, but for what contribution you can make to the enjoyment of others.”