Dunham was born on April 18, 1962, in Dallas, Texas. When he was three months old, he was adopted by real estate appraiser Howard Dunham, and his homemaker wife Joyce, who raised him in a devoutly Presbyterian household in an affluent Dallas neighborhood, as an only child.

He began ventriloquism in 1970 at age eight, when his parents gave him a Mortimer Snerd dummy for Christmas, and an accompanying how-to album. The next day he checked out a how-to book on ventriloquism from the library, and explained in 2011 that he still had it, remarking that he was “a thief in the third grade”. By the fourth grade, Dunham decided he not only wanted to be a professional ventriloquist, but the best one ever. Dunham began practicing for hours in front of a mirror, studying the routines of Edgar Bergen, and the how-to record Jimmy Nelson’s Instant Ventriloquism, finding ventriloquism to be a learned skill, similar to juggling, that anyone with a normal speaking voice can acquire. Dunham has explained that, as an only child, he enjoyed being alone, likening his solitude to a “warm blanket” with which he could explore his own thoughts and ideas, which prepared him for the solitude of living alone when he later moved to Los Angeles as a struggling comedian.

Dunham began performing for audiences as a teenager, in various venues such as school, church, and during his job at Six Flags. By his middle school years, he began to perform for banquets attended by local celebrities such as Dallas Cowboys quarterback Roger Staubach, having developed his style of lampooning those he performed for, using the puppets to say things too risque for him to say without them. Dunham’s television debut came in 1976 when the still prepubescent performer caught the attention of Dallas reporters like Bill O’Reilly, who interviewed Dunham for a local news story. Dunham later did commercials for Datsun dealerships in Dallas and Tyler while still in high school. While emceeing a high school talent show, he dealt with a heckler, and won over the rest of the audience. During this period he became so associated with his craft that he and one of his dummies “cowrote” a column in the school paper, and he would pose with his dummies for yearbooks as an inexpensive way to acquire professional photos of his act for promotional purposes. He was voted Most Likely to Succeed, and in 1980, after he graduated from high school, Dunham gave himself a career goal of obtaining, within ten years, an appearance on The Tonight Show Starring Johnny Carson, which was seen as the “holy grail” for comedians.

When Dunham was in the sixth grade, he began attending the Vent Haven ConVENTion in Fort Mitchell, Kentucky, an annual international meeting of ventriloquists that includes competitions, where he met Jimmy Nelson in person. Dunham has missed only one ConVENTion since then, in 1977. The organizers of the ConVENTion eventually declared Dunham a “retired champion”, ineligible from entering any more competitions, as other attendees were too intimidated to compete against him. The Vent Haven Museum devotes a section to Dunham, alongside Señor Wences and Dunham’s idol, Edgar Bergen.

He caught a break in 1985 when he was asked to join the Broadway show Sugar Babies with Mickey Rooney and Ann Miller, replacing an outgoing variety act. For the naive and devoutly-raised Dunham, Broadway was a new world filled with beautiful showgirls and crusty stagehands, and his first taste of entertainment industry egos came when Rooney called Dunham into his dressing room, and told him he was there for one reason alone: so that Rooney could change his costumes. He performed at the Westbury Music Fair on Long Island. These early experiences, in which he used characters like José Jalapeño on a Stick, taught him the value of modifying his act regionally, as the jalapeño jokes that worked well in Texas were not as well received by audiences in Long Island. After graduating from Baylor University in 1986, he continued honing his act in comedy clubs in the Southwest with new characters such as Peanut and José Jalapeño, but struggled against the perception he relates from fellow comedians that he was not a true comedian because he relied on props.

Little Jeff is a miniature version of Dunham himself, usually dressed in the same clothes Dunham wears during each show. His first onscreen appearance was in the 1989 television program A&E’s An Evening at The Improv. He later appeared in Jeff Dunham: Controlled Chaos as a puppet that Peanut used when attempting his hand at ventriloquism. Peanut named the doll “Little Ugly Ass-Jeff”, and uses him to insult Dunham.

At the end of 1988, Dunham was told by James McCawley, a talent booker for The Tonight Show Starring Johnny Carson, that Dunham would be given a spot on the coveted program. Though the 26-year-old Dunham was elated that his 10-year goal was arriving two years early, McCawley later cancelled Dunham’s appearance after attending, with Roseanne Barr, a public performance of Dunham’s the day before Dunham’s scheduled Tonight Show taping. McCawley informed Dunham on the day of the scheduled taping that he had been wrong in his initial assessment of Dunham, whom he now said was not ready for The Tonight Show. Dunham continued to tighten his act in Los Angeles clubs, performing the same six-minute segment with Peanut a total of nine times for McCawley over the next few months. Finally at the Ice-House in Pasadena in April 1990, after Dunham did the same segment, McCawley informed Dunham that he would finally get his Tonight Show appearance. Dunham and Peanut appeared on The Tonight Show Starring Johnny Carson on April 6, 1990, alongside guests Bob Hope and B.B. King. Following his bit, he was invited to sit on Johnny Carson’s couch, a mark of approval on Carson’s show. Upon sitting down next to Carson’s desk, Dunham pulled out Walter, who told Carson sidekick Ed McMahon, “Stop sending me all your damn mail.” At the time, Dunham saw his Tonight Show appearance as his big break, but was frustrated at his parents’ initial disapproval over Walter’s use of the words “hell” and “damn”, and he would toil in obscurity for another twelve years, continuing his stand up at venues such as The Improv chain, and appearing in small roles on TV. One of these was a 1996 episode of Ellen, in which he appeared with Walter. Dunham also appeared with Walter in a TV commercial for Hertz. Dunham would appear on The Tonight Show a total of four times, as well as similar TV venues such as Hot Country Nights, appearing in one segment with Reba McEntire. This exposure helped make Dunham a large theater headliner, a rare accomplishment for a ventriloquist, but by the mid-1990s, his television appearances had dwindled, and with them, so did his stage audiences.

Dunham met his first wife, Paige Brown, at the Comedy Corner in West Palm Beach, Florida. They began dating in December 1992. In May 1994, Dunham married Brown and adopted her one-and-a-half-year-old daughter, Bree. Their daughters Ashlyn and Kenna were born in 1995 and 1997, respectively. Dunham’s time away while performing proved a strain on the marriage, and in November 2008, he filed for divorce. By mid-2009, Dunham was in a relationship with fellow Texan Audrey Murdick, a certified nutritionist, personal trainer, and competition bodybuilder, and on December 25, 2011 they became engaged. On October 12, 2012, the couple married. On May 14, 2015, Dunham announced, via Facebook, that he and Audrey were expecting twin boys. In October, she gave birth to James Jeffrey and Jack Steven.

Dunham moved back to clubs, more than 200 appearances a year. To maintain a connection with his fan base, he would use question cards that he had audiences fill out for his performances to build a database, which was tailor-made for the burgeoning World Wide Web. Though he was voted Funniest Male Standup at the American Comedy Awards in 1998, his club work kept him away from his wife and daughters between two and three weeks each month, which put a strain on his marriage, and made paying bills for his expanded family difficult. By 2002, Dunham was hoping to obtain more TV work to raise his profile and ease his standup schedule. Such exposure was elusive until a successful appearance on The Best Damn Sports Show Period, where Dunham and Walter made jokes at the expense of co-hosts Tom Arnold, Michael Irvin, John Salley and John Kruk, generating laughter from them, and giving Dunham much-needed exposure. In 2003, Dunham was the frontrunner to replace Jimmy Kimmel on Fox NFL Sunday, but hosts Howie Long and Terry Bradshaw were not amenable to the idea of being upstaged by a puppet, and, as Dunham tells it, did not provide a welcoming atmosphere to Dunham, nor allow him to speak much during his appearance.

On July 18, 2003, Dunham appeared on Comedy Central Presents, his first solo appearance on Comedy Central. During his half hour piece, he showcased José Jalapeño on a Stick, Walter, an early version of Melvin the Superhero Guy and Peanut, whom Dunham had begun to merchandise into a line of dolls. The appearance was successful, but Comedy Central resisted giving Dunham more airtime, feeling that he was not a good fit for them. By 2005 Dunham decided to gamble on financing his own comedy DVD, Jeff Dunham: Arguing with Myself, which was taped in Santa Ana, California. Dunham’s manager, Judi Brown-Marmel, lobbied the network to air it, pointing to Dunham’s drawing power and merchandising profits, and arguing that the network needed more diverse content. Surprised by the high ratings of the first Blue Collar Comics concert movie that same year, the network began to reconsider its brand. In late 2006, Comedy Central aired Arguing with Myself, drawing two million viewers when it aired, and selling two million DVDs.

In 2003, BRASMA Publications released Dear Walter, a collection of questions asked of Dunham’s fictional curmudgeon at live performances, authored by Dunham and Walter Cummings. His autobiography, All By My Selves: Walter, Peanut, Achmed and Me, was published by Dutton in 2010.

In 2007, Dunham appeared as The Amazing Ken with José Jalapeño on a Stick in the Larry the Cable Guy feature film Delta Farce. His second special, Jeff Dunham: Spark of Insanity, was taped at the Warner Theater in Washington, D.C. that same year. It served not only to cement Dunham’s stardom, but to introduce his most controversial character, Achmed the Dead Terrorist, which became a viral Internet sensation. A clip of Achmed from Insanity attracted over 140 million hits on YouTube, making it the ninth most watched clip on that website as of October 2009.

By 2008, Dunham’s characters had crossed language barriers, with his specials dubbed for audiences in various countries such as France, and Dunham attracting requests for performances in South Africa, Australia, Norway, Denmark, China, and the Middle East. Jeff Dunham’s Very Special Christmas Special was taped at the Pabst Theater in Milwaukee, Wisconsin that same year, and premiered on Comedy Central on November 16, 2008, watched by 6.6 million people. It became available on DVD and Blu-ray on November 18, 2008. The special’s premiere was the highest rated telecast in Comedy Central’s history.

In September 2008, his career reached new heights as he began performing in arenas filled with tens of thousands of people. Dunham was somewhat wary of such large venues, but adapted by adjusting the timing of his often rapid exchanges with the puppets so that audience members farthest from the stage could have time to react.

In addition to his comedy specials, Dunham also released his first music album, Don’t Come Home for Christmas, on November 4, 2008. It contains original Christmas songs as well as a parody of “Jingle Bells” by Achmed entitled “Jingle Bombs”. All the songs, with the exception of “Jingle Bombs”, were written and accompanied by Brian Haner, who joined Dunham’s act as “Guitar Guy”. His first onscreen appearance was in Jeff Dunham’s Very Special Christmas Special.

In January 2008, Dunham was voted by fans the Top Comic in Comedy Central’s “Stand-Up Showdown”. He is the only person ever to win the “Ventriloquist of the Year” Award twice, was nominated “Comedian of the Year” by the TNN Music City News Country Awards, and has drawn praise from the Dallas Morning News for his technique and timing. Critics, such as Randee Dawn of The Hollywood Reporter, accused Dunham’s characters of being racist caricatures, sexist, and homophobic.

In 2008, a TV commercial for a ringtone which featured Dunham’s character Achmed the Dead Terrorist (see Characters below) was banned by the South African Advertising Standards Authority after a complaint was filed by a citizen stating that the ad was offensive to Muslims, and portrayed all Muslims as terrorists. Dunham responded that “Achmed makes it clear in my act that he is not Muslim.” However, the ASA noted that the name Achmed was of Arab origin and was one of the names of Muhammad. Dunham responded, “I’ve skewered whites, blacks, Hispanics, Christians, Jews, Muslims, gays, straights, rednecks, addicts, the elderly, and my wife. As a standup comic, it is my job to make the majority of people laugh, and I believe that comedy is the last true form of free speech … I’m considering renaming Achmed ‘Bill'”, he added. Dunham has conceded that he does exhibit particular sensitivity to the “conservative country crowd,” or those characterized by “basic Christian values”, as they are one of his largest constituencies, and part of his upbringing.

In March 2009, Dunham signed a multi-platform deal with Comedy Central. It included a fourth stand-up special to air in 2010, DVDs, a consumer products partnership, a 60-city tour beginning in September 2010, and an order for a television series called The Jeff Dunham Show that premiered on October 22, 2009. Despite having the most-watched premiere in Comedy Central history, and higher average ratings than other shows on that network initially, the show was canceled after only one season, amid poor reviews, dwindling ratings and higher production costs than other Comedy Central shows.

Dunham appeared in a guest role with Bubba J on NBC’s sitcom 30 Rock, playing a ventriloquist named Rick Wayne and his dummy Pumpkin from Stone Mountain, Georgia. In November 2009 Dunham also appeared with Walter in “Hart to Hart”, an episode of the Disney Channel series Sonny With a Chance, as two security guards. He appeared in the 2010 Steve Carell/Paul Rudd comedy, Dinner for Schmucks, as Lewis, with a new puppet named Diane.

Dunham was heckled and criticized for mocking TV critics during a July 2009 press tour to promote his then-upcoming Comedy Central TV series, The Jeff Dunham Show, as well as Comedy Central programming chief Lauren Correo. In October 2009 The Jeff Dunham Show enjoyed good initial ratings, but was not well liked by critics, some of whom either questioned the wisdom of translating his act into a series, or cited Dunham, his previous specials, or ventriloquism itself as reasons for disliking the show.

By June 2009, the sketch in which Dunham introduced Achmed had amassed nearly 200 million views on YouTube. The large, round, articulated eyes of puppets such as Achmed and Achmed Junior are constructed by the same effects artist who created the dinosaur eyes for the Jurassic Park films. The character starred in Achmed Saves America, an animated film that premiered on Country Music Television in March 2014. In the film, which depicts the mishap that led to the character’s skeletonization, Achmed finds himself in an American town called Americaville, which he plots to blow up, before developing an affinity for American culture.

Diane first appeared with Dunham in the 2010 film Dinner for Schmucks as “Debbie”, his character’s “wife”. She made her stand-up debut in Dunham’s Identity Crisis Tour 2010.

Dunham has harbored a love of helicopters since childhood and is fond of building and flying his own kit helicopters from Rotorway helicopter kits. At the time he finished writing his autobiography in June 2010, he was beginning to build his fourth kit. He is also an aficionado of muscle cars and Apple, Inc. products. According to the July 16, 2012, television documentary The Batmobile, Dunham owns the original Batmobile used in the Tim Burton film Batman, which he had outfitted with Corvette engine to make it street legal.

His fourth special, Jeff Dunham: Controlled Chaos, premiered on September 25, 2011, on Comedy Central. His fifth special, Minding the Monsters, which was taped in Savannah, premiered on Comedy Central on October 7, 2012. His sixth special, All Over the Map, which was taped in various international cities, premiered on Comedy Central on November 16, 2014.

On March 28, 2014, Country Music Television premiered Achmed Saves America, an animated film starring Achmed the Dead Terrorist.

In a 2014 show in Malaysia, the government requested that he not use or name Achmed in his show. Due to the restriction, but to avoid disappointing fans, Achmed was renamed to be “Jacques Merde, the Dead French Terrorist” (Jacques Merde meaning “Jack Shit”).

Dunham’s seventh special, Unhinged in Hollywood, premiered on September 17, 2015. Rather than premiering on Comedy Central, the special instead aired on NBC.

In the 2020 United States presidential election, Dunham adapted the Walter puppet into “Wonald Grump” and “Ben Hiden,” caricatures of Donald Trump and Joe Biden, respectively, for a mock debate moderated by Achmed.