Martin was born in Kokomo in Howard County in north central Indiana. For a short time, the Martins moved to San Antonio, Texas, but soon returned to Indiana. As a child, he excelled at swimming and diving; he was nicknamed "T-Bone Martin" because of his diving expertise. At 17, he won the National Junior Springboard Diving Championship. He served as a swimming instructor in the United States Navy during World War II and was a member of the diving team at the University of Michigan in Ann Arbor, Michigan. He entered the adult National Springboard Diving competition in hopes of gaining a berth on the U.S. Olympic team but finished third in the competition
After the war, Martin moved to Los Angeles, California, and worked as a swimming instructor and as a swimming extra in water scenes in films. He earned bit roles in a number of pictures and soon gained frequent character roles in films and television through the 1950s, having appeared in such programs as the western anthology series, Frontier on NBC and the syndicated American Civil War drama Gray Ghost. He was cast in 1955 as Landry Kersh in the episode "Shadow of God" on the ABC religion anthology series, Crossroads. He gave a memorable performance as a mentally retarded man in the "Cooter" episode of Gunsmoke (1955).
Martin appeared in the first Brian Keith series, Crusader, a Cold War drama on CBS. He guest starred as a circus tightrope walker in one of the 1957 episodes of CBS's Have Gun, Will Travel. He portrayed a henpecked soldier in a 1958 episode of the syndicated western series, Boots and Saddles. That same year, he played the lead in the episode "Pete Henke" of NBC's western Jefferson Drum.
In 1959, Martin played Polk, with Denver Pyle as Houston, in the episode "No Place to Stop" of the CBS western series, The Texan, starring Rory Calhoun as Bill Longley. In another 1959 western series, Martin was cast as Deputy Jess in the episode "Johnny Yuma" of ABC's The Rebel, starring Nick Adams.
In 1960, Martin guest starred in James Whitmore's ABC crime drama, The Law and Mr. Jones. In 1962, Martin was cast as Harold Horton in "The Chocolate Cake Caper" of the CBS sitcom, Pete and Gladys, starring Harry Morgan and Cara Williams. He guest starred in Jack Lord's ABC adventure/drama series, Stoney Burke.
In 1963, he was cast as Private Anton Copang in the episode "Walk Through the Badlands" of the ABC/Warner Brothers western series, The Dakotas. In 1966, Martin appeared twice as "Cousin Fletch" in the short-lived ABC comedy western The Rounders, with Ron Hayes, Patrick Wayne, and Chill Wills. Earlier, he had guest starred with Harry Morgan and Cara Williams in their CBS sitcom, Pete and Gladys.
Martin's distinctive, reedy voice and menacing demeanor made him ideal for villainous roles in many of the best-known westerns of the 1950s and 1960s, including The Horse Soldiers and The Man Who Shot Liberty Valance, both directed by John Ford and starring John Wayne. His lunatic turn in the latter film as Lee Marvin's character's insanely sadistic henchman, gleefully giggling in anticipation of each horrendous atrocity, remains a particularly memorable performance. Martin also excelled in comedy, playing an incompetent "Indian agent" in the John Wayne film, "McClintock," and as a hapless horse trader in the 1969 film, "True Grit." By the late 1960s, Martin was almost as well-known a figure as many top-billed stars. In 1967, the same year as his role in Cool Hand Luke, he appeared in the episode "A Mighty Hunter Before the Lord" of NBC's The Road West series starring Barry Sullivan. In 1972, he appeared as James Garner's uncle in the "Zacharia" episode of NBC's Nichols.
The play The Time of Your Life was revived in March 17, 1972 at the Huntington Hartford Theater in Los Angeles with Martin, Henry Fonda, Richard Dreyfuss, Gloria Grahame, Lewis J. Stadlen,Ron Thompson, Jane Alexander, Richard X. Slattery and Pepper Martin among the cast with Edwin Sherin directing.
Martin appeared in all three of the classic Westerns released in 1969: Sam Peckinpah's The Wild Bunch (as Coffer, a bloodthirsty bounty hunter); George Roy Hill's Butch Cassidy and the Sundance Kid (as Percy Garris, the "colorful" Bolivian mine boss who hires the two title characters); and Henry Hathaway's True Grit (as Colonel Stonehill, a horse dealer). He frequently acted alongside L. Q. Jones, who in real life was one of his closest friends.
Though he usually appeared in supporting roles, he had major parts in Hannie Caulder, The Brotherhood of Satan (both 1971), Pocket Money (1972) with Paul Newman and Lee Marvin, andSSSSSSS (1973). Martin later appeared in another George Roy Hill film, Slap Shot (1977), again with Paul Newman, as the cheap general manager of the Charlestown Chiefs hockey club. He appeared six times each with both John Wayne and Paul Newman. Strother Martin can also be seen in Cheech and Chong's Up in Smoke (1978) as Arnold Stoner, the father of Tommy Chong's character Anthony.
Martin made many guest appearances on Gunsmoke, including the two-part episode "Island in the Desert," in which he portrayed a crazy desert hermit named Ben Snow. He also made many guest appearances on Perry Mason throughout the nine-year run from 1957-1966, including a college employee in "The Case of the Brazen Bequest", and the murderer in "The Case of the Drowsy Mosquito". In 1963, he appeared in Glynis Johns's short-lived comedy series Glynis in the episode "Ten Cents a Dance." In 1965, Martin appeared in the episode "Most Precious Gold" of the NBC comedy/drama series Kentucky Jones, starring Dennis Weaver. In 1965, he guest-starred as Meeker in the episode "Return to Lawrence" on the ABC western The Legend of Jesse James. In 1966, he guest-starred in the Lost In Space episode "Blast Off Into Space" as a gritty mining engineer. On a Gilligan's Island episode, Martin played a man living supposedly alone on the island for a radio show contest. He also starred in a two- part The Rockford Files 1977 episode as T.T. Flowers The Trees, the Bees, and T.T. Flowers, an episode that took on urban invasion and the environment. One of his last acting jobs was as host of Saturday Night Live on April 19, 1980. In one of the skits, Martin played the strict owner of a French Language camp for children - a role based on his role as the prison captain from the film, Cool Hand Luke. He even paraphrased his most famous line from the film - "What we have here is failure to communicate BI-LINGUALLY!" In another, he played a terminally ill man who videotaped his last will and testament. This episode was supposed to be rerun during the summer of 1980, but was pulled and replaced with another episode due to his death.
Martin was married to Helen Meisels-Martin from 1967 until his death. He died of a heart attack in 1980 at the age of 61. His widow, who was ten years his senior, died in 1997. Her ashes are interred with Martin's in Court of Remembrance, Columbarium of Radiant Dawn, at Forest Lawn Memorial Park in the Hollywood Hills.