Born in Yakima, Washington and spending most of his childhood in Peoria, Illinois, Kinison was the son of Marie and Samuel Kinison, Pentecostal preachers. His father pastored several churches around the country, receiving little income. Sam later attended East Peoria Community High School in East Peoria, Illinois. He also lived in Tulsa, Oklahoma, for a while with his parents. He followed in his father's footsteps as a Pentecostal preacher before becoming a comedian. Recordings of his sermons reveal that he used a "fire and brimstone" style, punctuated with shouts similar to the ones he would later use in his stand-up routines. He attended Pinecrest Bible Training Center in Salisbury Center, New York. After he and his first wife were divorced, he abandoned preaching and took up comedy as a profession.
Sam Kinison began his career in Houston, Texas, where he performed in small clubs. It was not until his appearance on HBO's Rodney Dangerfield's Ninth Annual Young Comedians Special in the summer of 1984 that he became well known. His appearance on the special is widely considered to be his breakthrough performance. Later, during Kinison's appearance on Late Night with David Letterman in 1985, Letterman's introduction of Kinison warned his audience: "Brace yourselves. I'm not kidding. Please welcome Sam Kinison."
Kinison played on his former role as a Bible-preaching evangelist, taking satirical and sacrilegious shots at the Bible, Christianity and famous Christian evangelist scandals of his day. Kinison's daring comedy helped shoot him to stardom. On several videos of his stand-up routines, a shot of his personalized license plate reveals the words "EX REV".
Kinison made his film debut in Rodney Dangerfield's 1986 film Back to School, playing a short-tempered professor.
Kinison was associated with the Los Angeles rock music scene and was occasionally accompanied by a touring band. He also gained a reputation as having a prodigious appetite for drugs and alcohol.
In 1988, Kinison recorded a novelty version of The Troggs' "Wild Thing", which appeared on his album Have You Seen Me Lately?. The video was a hit on MTV, as it featured cameos of Rodney Dangerfield, as well as many well-known rock musicians, including Steven Tyler and Joe Perry of Aerosmith, Ratt, Slash and Steven Adler of Guns N' Roses, Billy Idol, Steve Vai, Dweezil Zappa, Richie Sambora, and Tommy Lee, and a raunchy "roll on the mat" dance with Jessica Hahn. Also in 1988, Kinison appeared in the music video for the Bon Jovi single "Bad Medicine".
Kinison appeared in the memorable episode "It's a Bundyful Life: Part 2" (1989) of Married... with Children, as Al Bundy's guardian angel, who shows him what life would be like without him born (a take-off of It's a Wonderful Life). Kinison was an early choice to play the character of Al Bundy with Roseanne Barr as Peggy Bundy. However, both of their managers rejected the idea.
During one notable Tonight Show performance, Kinison delivered what began as a straightforward version of Elvis Presley's "Are You Lonesome Tonight?", which descended into angry ranting during the spoken breakdown, and then segueing back into a straightforward sung ending.
Some of Kinison's most spontaneous moments came during his frequent appearances on The Howard Stern Show. He made an angry phone call on-air to Bobcat Goldthwait, and he embarrassed comedienne Judy Tenuta to the point of driving her off the show. His most notorious stunt resulted in an on-air feud with Stern. Kinison made an on-air promise to bring to the show members of the band Bon Jovi, with whom Stern was feuding, but they did not show up, nor did Kinison. Stern's reaction was swift and vindictive, and Kinison eventually apologized, but not before comedian Gilbert Gottfried and Stern ridiculed an emotionally charged phone call between Stern and Kinison, in which both stars used the words "man" and "dude" so often that the playback was used as a bit on the show.
Stern and Kinison eventually made up and paired on Stern's pay-per-view special, U.S. Open Sores. In the early 1990s Stern, who purchased the movie rights to Kinison's biography, reported that HBO would make Brother Sam with Kinison being played by Dan Fogler.
In 1991, Kinison starred in the Fox Network television show Charlie Hoover, in which he played the inner voice of the title character, appearing as a 12-inch tall man. The show lasted only seven episodes before being canceled.
In an interview with Sam's brother and manager Bill Kinison, Bill mentioned movie deals that were in development at the time of his death; one such deal was a movie with Arnold Schwarzenegger, and another with Rick Moranis. On April 5, 1992, Kinison married girlfriend Malika Souiri.
In February 2011, the Toronto Sun reported that Sam Kinison fathered a child with the wife of his best friend and opening act, Carl La Bove, who had been paying child support for the girl for nearly 13 years. La Bove filed legal papers claiming the girl is Kinison's, and DNA tests taken from Kinison's brother Bill show a 99.8% likelihood that Sam Kinison is the father of the unnamed woman, who was 21 at the time of the Toronto Sun story, and excluded La Bove as her father. On April 10, 1992, five days after he married his girlfriend Malika Souiri, Sam Kinison died after his white 1989 Pontiac Trans Am was struck on U.S. Route 95, four miles (6 km) north of Interstate 40 and several miles west of Needles, California, by a pickup truck driven by a 17-year-old male who had been drinking alcohol. An autopsy found that Kinison had cocaine, tranquilizers and painkillers in his bloodstream. His wife survived the accident..
Kinison is interred with family members at the Memorial Park Cemetery in Tulsa, Oklahoma. His grave marker includes the unattributed quote, "In another time and place he would have been called prophet." Sam used to perform at the old Ciro's nightclub, now called The Comedy Store on Sunset. It's owned by Mitzi Shore, Paulie’s mom. Sam's show was constantly troubled by the ghosts that apparently objected to Sam's loud performances.