Born John Augustus Kelly, Jr. in Astoria, Queens, New York, one of four children, to Ann Mary “Nan” (née Walsh) and John Augustus Kelly, Sr. “Jackie,” as he was called as a child, came from a prominent theatrical family. His mother, Nan Kelly, had been a popular stage actress and John Robert Powers model. Kelly’s father was a theater ticket broker, and after he moved the family to Hollywood, entered the real estate business. His sister, Oscar-nominated actress Nancy Kelly, was a movie child star turned prominent leading lady. His other two siblings, Carole and William Clement (25 July 1934 – 6 April 1983), also tried show business. When the Kellys were children, their mother would not serve them meat or give medication when they were sick.  Kelly made his film debut in an uncredited role in the 1939 biopic The Story of Alexander Graham Bell, opposite Don Ameche and Loretta Young. On July 15, 1954, Kelly played the gunfighter, cattleman, and bandit Clay Allison in the syndicated television series Stories of the Century, starring and narrated by Jim Davis.  In 1955-1956 television season, Kelly starred in a series based on the 1942 feature film Kings Row. He played Dr. Parris Mitchell, a young psychiatrist coping with the narrow-minded environment of his small town. King’s Row was one-third of the Warner Bros. Presents wheel series, hosted by Gig Young. It rotated at the scheduled hour of 7:30 Eastern on Tuesday with a similar television version of the popular movie Casablanca as well as the new ABC Western series Cheyenne starring Clint Walker.  After the series ended in 1956, Kelly appeared in Forbidden Planet (1956) and She-Devil (1957), along with guest roles on Fireside Theater, Schlitz Playhouse of Stars, Lux Video Theatre, and Gunsmoke.

The various anti-heroic Mavericks were dapper professional poker-players roaming the Old West with the benefit of superb scripts. The series had an enormous cultural impact during a time when there were only three television networks and most cities had only three TV channels to choose from.  Maverick’s demanding filming schedule had caused production to lag behind early on. The producers decided to give Bret Maverick (James Garner) a brother so as not to run out of episodes long before the end of the season. Thus, Kelly was introduced as Bart Maverick in “Hostage!”, the eighth episode of the series. While he may not have matched Garner’s popularity on Maverick, Kelly did have his enthusiastic admirers. Possessing a deep voice, a John Barrymore-like profile and an easy-going screen presence, Kelly enjoyed an attentive following among female viewers of the series. Series creator Roy Huggins was extremely critical of Kelly’s acting in Huggins’ Archive of American Television interview, noting that Kelly “dropped a funny line like a load of coal,” but mentioned that he liked Kelly, who was more amusing than Garner “off camera.”

Kelly shared the lead with James Garner in one of the show’s most-discussed episodes, “Shady Deal at Sunny Acres”, on which the first half of the 1973 movie The Sting appears to be based. The pair also co-starred in the famous “Pappy” episode in which Garner played the brothers’ much-quoted father Beauregard “Pappy” Maverick, in addition to his regular role of Bret. Aided by trick photography, Bret and Pappy play cards together in one scene (Kelly had a dual role in the episode as well, playing Bart and elderly Uncle Bentley Maverick). Bart also rescued Bret at the climax of “Duel at Sundown”, in which Garner fist fought guest star Clint Eastwood. Since Garner enjoyed seniority on the series, he had first choice of which part he would play in the two-brother episodes, which delineated the brothers as “Maverick 1” and “Maverick 2” in the scripts, giving him an enormous advantage. All but one script during the show’s first two years were written with Garner in mind regardless of which actor would eventually be cast. Roy Huggins insisted that the writers visualize Garner as Maverick while writing the scripts. The sole exception to this edict during the first two seasons was “Passage to Fort Doom,” written with Kelly in mind as a lark for the writers.  Although the “solo” episodes in which Bart appeared tended to be somewhat more dramatic than the Bret episodes, Kelly displayed his comedic skills in lighter Maverick outings such as “Hadley’s Hunters” and “The People’s Friend.” Kelly actually appeared in more episodes of Maverick than James Garner, who left the show following a contract dispute in 1960. Kelly appeared in 83 episodes; Garner in only 65. In the wake of Garner’s departure, Roger Moore stepped in to play Bart’s cousin Beau Maverick in fourteen episodes, sharing the screen with Kelly in three of them, while Robert Colbert appeared in two installments as a third brother named Brent, one of which briefly featured Kelly.

When Maverick ended in 1962, Kelly continued acting with roles in a number of films and television shows. In 1962, he played the lead in Red Nightmare (also known as The Commies Are Coming, the Commies Are Coming in its derisive 1985 video re-release incarnation) a Cold War film narrated by Jack Webb in which Kelly’s character wakes up one morning to discover that America has been taken over by Communists.  On December 30, 1963, Kelly appeared with Barbara Bain in “The Fenton Canaby Story” on ABC’s Wagon Train. Canaby is a former trailmaster with a dark secret he refuses to discuss. He is attracted to Lucy Garrison, a young woman with her own questionable past played by Barbara Bain, long before Mission: Impossible!. Virginia Gregg plays Grace Lowe, who blames Canaby for her husband’s death.  Kelly co-starred in Commandos (1968) opposite Lee Van Cleef, and as a villain dressed almost exactly like Bart Maverick in Young Billy Young (1969) with Robert Mitchum. From 1969 to 1971, Kelly hosted the NBC daytime game show Sale of the Century but was eventually replaced by Joe Garagiola. He was also briefly a series regular in Get Christie Love! (1974) and The Hardy Boys/Nancy Drew Mysteries (1978), and performed many lucrative television commercial voice-overs.  In 1977 Kelly appeared as obstreperous villains for a few moments in two Rockford Files episodes starring James Garner. The first appearance was in the season 3 episode, “The Becker Connection,” and the second was the first show of season 4, “Beamer’s Last Case” as a jealous husband. In 1978, he briefly appeared as Bart Maverick and was again paired with Garner in the TV-movie The New Maverick and in Garner’s TV series Bret Maverick (1981; Kelly appeared momentarily at the end of the final episode of the show and would have become a regular had it been renewed). Kelly also showed up on a 1983 episode of The Fall Guy, costumed as Maverick but basically playing himself in a storyline that rounded up many classic TV cowboys.  In 1991, he reprised the role of Bart Maverick one last time in the TV movie The Gambler Returns: The Luck of the Draw, a Kenny Rogers vehicle briefly featuring more than a dozen 1950s television series cowboys. Kelly’s brief dialogue consisted almost exclusively of variations on the phrase, “you can’t have a real poker game without a Maverick.”

Kelly’s acting roles became less frequent in the late 1970s as he became more involved in real estate and local politics. He started buying real estate in Huntington Beach in the mid 1960s and moved there permanently in 1971.  He formed August II, Inc., to hold the real estate assets in June 1965 in Huntington Beach. His wife, Jo, became a real estate broker and did much of the business management of the real estate business, especially while Kelly was involved with Huntington Beach city government.  During the 1980s and early 1990s he served as city councilman and mayor in Huntington Beach, campaigning with the slogan “Let Maverick Solve Your Problems.”  Kelly married actress May Wynn (Donna Lee Hickey) on October 14, 1956. They separated in February 1964 and were divorced on October 19, 1964. She stated in court that they had been arguing a lot the last two years and he started staying out all night.  Following the divorce he later dated Karen Steele for a short time.  He married Jo Ann Smith in Las Vegas, Nevada on October 16, 1969. The following November their daughter Nicole was born.  On April 28, 1992 he suffered a heart attack. Jack Kelly died of a stroke at Humana Hospital in Huntington Beach, California, November 7, 1992. In addition to his sister Nancy he was survived by his second wife, Jo, and their daughter, Nicole.  Jo became an “extra” in film and television productions, helped others learn the business, and wrote a book about it, The Truth about Being an Extra (2006).  His daughter, Nicole K. Kelly, is the founder of and executive producer at August II Productions.