Gibson was born on September 21, 1935 as James Bateman in Germantown, Philadelphia, the sixth of seven children of Edmund Albert Bateman and his wife Dorothy (née Cassidy). He attended Saint Joseph's Preparatory School, where he was president of the drama club.
After graduating from the Catholic University of America in Washington, D.C., he served as an intelligence officer in the United States Air Force with the 66th Tactical Reconnaissance Wing in France from 1957 to 1960. Early in his career as a professional entertainer, he developed a comedy act in which he played a poet from Fairhope, Alabama. He adopted the stage name Henry Gibson, which is an oronym for the name of famed Norwegian dramatist Henrik Ibsen. He is also known to have used the name Olsen Gibson.
Gibson's performing career began at the age of seven. He appeared in many stage and theater productions. Gibson made many appearances on Tonight Starring Jack Paar between 1957 and 1962, often reciting his poetry. His career took off when he performed in the Jerry Lewis film The Nutty Professor (1963). This was followed in 1964 by his poetry-reciting cowboy character Quirt Manly on the popular show The Beverly Hillbillies. Around this time, Gibson also appeared on an episode of My Favorite Martian.
Gibson spent three years as part of the Laugh-In television show's cast, where he was nominated for a Golden Globe in 1971. He often played "The Poet", reciting poems with "sharp satirical or political themes". Gibson would emerge from behind a stage flat, wearing a Nehru jacket and "hippie" beads and holding an outlandishly large artificial flower. He would bow stiffly from the waist, state "[Title of poem] — by Henry Gibson" in an ironic Southern US accent, again bow stiffly from the waist, recite his poem and return behind the flat. Gibson's routine was so memorable that John Wayne actually performed it once in his own inimitable style: "The Sky — by John Wayne. The Sky is blue/The Grass is green/Get off your butt/And join the Marine(s)!", whereupon Wayne left the scene by smashing through the flat. Gibson also regularly appeared in the "Cocktail Party" segments as a Catholic priest, sipping tea. He would put the cup on the saucer, recite his one-liner in a grave and somber tone, then go back to sipping tea. In 1962, Gibson had issued a comedy album on Liberty records, entitled "Alligator." The album was rereleased in 1968, now entitled "...by Henry Gibson," following his success on "Laugh-In." The liner notes perpetuated the origin story of his being a country boy from Fairhope, Alabama. The album did not reach the Billboard Top 200 in either release. Around this time, Gibson also made recurring appearances in the 1969–1974 anthology Love, American Style.
During the 60s, Gibson had appeared on The Dick Van Dyke Show reading the poem "Keep a-Goin'", which he later turned into a song in the Robert Altman movie Nashville (1975). Notably, he was nominated for a Golden Globe Award for his portrayal of country music star Haven Hamilton in the film and won the National Society of Film Critics award for the role. The Nashville Tennessean called Gibson “the male superstar most surely to be in line for an Academy Award" and hailed his performance as being “so real to Music Row habitués as to be frightening.” Gibson appeared in three other films directed by Altman: The Long Goodbye (starring Elliott Gould), A Perfect Couple, and Health.
In 1978, he appeared in The New Adventures Of Wonder Woman as the arch-villain Mariposa. Two years later, he appeared on The Dukes of Hazzard as Will Jason (Squirt) in the second-season episode "Find Loretta Lynn". The same year, he played the leader of the "Illinois Nazis" in the John Landis film The Blues Brothers; this became one of his best-known film roles. The next year, he appeared in The Incredible Shrinking Woman.
In the 1989 Joe Dante comedy The 'Burbs, starring Tom Hanks, Gibson played the villain. He reunited with director Dante a year later when Gremlins 2: The New Batch was released in 1990, performing a cameo as the office worker who is caught taking a smoking break on camera and fired by the sadistic boss. 1996 saw him playing an unusual dramatic role as former train conductor Robinson in the independent film Color of a Brisk and Leaping Day with Michael Stipe. That year, he was also the voice of Adolf Eichmann in Keith Gordon's film adaptation of Kurt Vonnegut's novel Mother Night. During 1999, Gibson made an appearance in another drama, Paul Thomas Anderson's Magnolia, as an eccentric barfly who antagonizes former child prodigy Donnie Smith, played by William H. Macy.
Gibson also worked frequently as a voice actor in animation, most notably portraying Wilbur the pig in the popular Hanna-Barbera children's movie Charlotte's Web (1973). He later worked for the company again on the cartoon The Biskitts. Additionally, Gibson's voice work was featured on The Grim Adventures of Billy & Mandy as Lord Pain, King of the Hill as reporter Bob Jenkins, and Rocket Power as grouchy neighbor Merv Stimpleton.
Later television work included a guest role on Star Trek: Deep Space Nine playing the Ferengi Nilva in the 1998 episode "Profit and Lace". Gibson also had a leading role in a season 5 episode of Stargate SG-1 entitled "The Sentinel" as the character Marul. His last major roles were in the 2005 film Wedding Crashers as Father O'Neil, and on the television show Boston Legal as supporting character Judge Clark Brown.
On April 6, 1966, Gibson married Lois Joan Geiger, who was five years his senior. They had three sons together – Jonathan David Gibson, an executive at Universal Pictures, Charles Alexander Gibson, a director and visual effects supervisor, and James Gibson, a screenwriter. His wife died on May 6, 2007, at age 77.
Gibson died of cancer on September 14, 2009 at his home in Malibu, California, a week before his 74th birthday. He was cremated at the Westwood Village Memorial Park Cemetery.