Before leaving for college, he worked as a caddie at the Lincoln Country Club. He also began performing magic shows for $35 a night under the tutelage of Gene Gloye. In 1952, Cavett attended the convention of the International Brotherhood of Magicians in St. Louis, Missouri, and won the Best New Performer trophy. Around the same time, he met fellow magician Johnny Carson, 11 years his senior, who was doing a magic act at a church in Lincoln.

He was cast in a film by the Signal Corps, but further jobs were not forthcoming. He was an extra on The Phil Silvers Show in 1959, a TV remake of the film Body and Soul for the DuPont Show of the Month the same year, and Playhouse 90 (“The Hiding Place”) in 1960. He briefly revived his magic act while working as a typist and as a mystery shopper in department stores. Meanwhile, his girlfriend and future wife Carrie Nye landed several Broadway roles.

In 1960, aged 23, Cavett was living in a three-room, fifth-floor apartment on West 89th Street in Manhattan for $51 a month, equal to $441 today.

Cavett appeared on the show in 1961, acting as interpreter for Miss Universe of 1961, Marlene Schmidt of Germany.

Cavett began a brief career as a stand-up comic in 1964 at the Bitter End in Greenwich Village. His manager was Jack Rollins, who later became the producer of nearly all of Woody Allen’s films. One of his jokes from this period was:

While taking a class at Yale School of Drama as an undergraduate, Cavett met his future wife, Caroline Nye McGeoy (known professionally as Carrie Nye), a native of Greenwood, Mississippi. After graduation, the two acted in summer theater in Williamstown, Massachusetts; and Cavett worked for two weeks in a local lumberyard to be able to buy an engagement ring. On June 4, 1964, they were married in New York. They remained married until Nye’s death in 2006. In 2010, Cavett married author Martha Rogers in New Orleans, Louisiana. From this marriage, Cavett has two step-children. Rogers and Cavett have lived in Montauk, New York, but as of 2019, reside in Ridgefield, Connecticut.

While at Time, Cavett wrote a letter to film comedian Arthur Jefferson, better known as Stan Laurel of the comedy team of Laurel and Hardy. The two soon met at Laurel’s Hollywood apartment. On the evening of that first visit, Cavett wrote a tribute to him that Paar read on his show. Laurel saw the broadcast which he deeply appreciated. Cavett visited the legendary comedian several times. Their final time together came three weeks prior to Laurel’s death in 1965.

In 1965, Cavett did some commercial voiceovers, including a series of mock interviews with Mel Brooks for Ballantine beer. In the next couple of years he appeared on game shows, including What’s My Line. He wrote for Merv Griffin and appeared on Griffin’s talk show several times, and then on The Ed Sullivan Show. In the late 1960s or early 1970s, he narrated a National Association of Broadcasters PSA featuring A Boy Wandering Around A Forest.

In 1968, after the premiere of the international film Candy (1968), Cavett went to a party at the Americana Hotel, where those who had just seen the film were being interviewed for TV.. He later said “When the interviewer, Pat Paulsen, got to me, he asked what I thought the critics would say about Candy. I said I didn’t think it would be reviewed by the regular critics, that they would have to reconvene the Nuremberg Trials to do it justice. He laughed and asked what I had liked, and I said I liked the lady who showed me the nearest exit so that I would not be forced to vomit indoors.”

In 1968, Cavett was hired by ABC to host This Morning. According to a New Yorker article, the show was too sophisticated for a morning audience, and ABC first moved the show to prime time, and subsequently to a late-night slot opposite Johnny Carson’s The Tonight Show.

Intermittently since 1968, Cavett has been host of his own talk show, in various formats and on various television and radio networks:

Cavett has been nominated for at least 10 Emmy Awards and has won three. In 1970, he co-hosted the Emmy Awards Show (from Carnegie Hall in New York) with Bill Cosby (from Century Plaza in Los Angeles). His most popular talk show was his ABC program, which ran from 1969 to 1974. From 1962 to 1992, The Tonight Show Starring Johnny Carson was arguably the most popular late night variety and talk show. Unlike many contemporary shows that attempted to compete with Carson in the same timeslot but were quickly cancelled, Cavett managed to remain on the air for five years.

On February 11, 1970, Cavett hosted a tribute to the life and works of Sir Noël Coward, who had just been knighted in December 1969. Along with Coward, the other guests were Alfred Lunt, Lynn Fontanne, and Tammy Grimes, and Brian Bedford (who were enjoying a successful run on Broadway in the revival of Coward’s play, Private Lives). In reviewing the show for The New York Times, television critic Jack Gould said “The age of youth? Balder dash! The over‐70 set walked off yesterday morning with a television program that combined the engaging qualities of lightly recalled nostalgia, the sophisticated stiletto, and a demonstration of genuine affection that had more substance than adolescent wails on how love will save the world. Sir Noel Coward, Alfred Lunt and Lynn Fontanne, friends of a lifetime, met on Dick Cavett’s show on the American Broadcasting Company network. They exchanged quips, pleasantries and thoughts about the theater with the beguiling charm of talented luminaries. Mr. Cavett was clearly overawed, and for once, the ad libs frequently went over his head. It was an enchanting show…and the badinage was warm and delightful … a fun night, and to take out of context a line or here or there could not convey the whole. To go to bed with a chuckle provided by gifted and nice people, onstage as off, is review enough.”

Cavett was present when actor Marlon Brando broke the jaw of paparazzo photographer Ron Galella on June 12, 1973. Galella had followed Cavett and Brando to a restaurant after the taping of The Dick Cavett Show in New York City.

Cavett narrated the HBO documentary series Time Was. Each episode covered a decade, ranging from the 1920s to the 1970s. The show originally aired in November 1979 and ran for six months. Cavett also hosted a documentary series for HBO in the early 1980s titled Remember When… that examined changes in American culture over time, as well as HBO’s monthly review series HBO Magazine.

In 1980 Cavett experienced what he characterized as his “biggest depressive episode”. While on board a Concorde before takeoff, Cavett broke out into a sweat and became agitated. After he was removed from the plane, Cavett was taken to Columbia Presbyterian Hospital in New York City, where he later underwent electroconvulsive therapy. Regarding this method of treatment, Cavett is quoted as saying, “In my case, ECT was miraculous. My wife was dubious, but when she came into my room afterward, I sat up and said, ‘Look who’s back among the living.’ It was like a magic wand.”

In April 1981, Cavett traveled to Stockholm, Sweden, to interview pop group ABBA on the occasion of their tenth anniversary as a group. The special, titled Dick Cavett Meets ABBA, was taped by the Swedish TV network SVT and was broadcast mainly in Europe. In the mid 1980s, Cavett took over for Jack Carney as host of The Comedy Show, syndicated from KMOX in St. Louis.

Cavett has appeared as himself in various other television shows, such as The Odd Couple, Kate & Allie, Cheers, and The Simpsons episode “Homie the Clown”. He also appeared in Robert Altman’s HealtH (1980) and in a cameo in A Nightmare on Elm Street 3: Dream Warriors (1987) as part of a dream sequence, turning into Freddy Krueger and coming after his guest, Zsa Zsa Gabor, halfway through. In Tim Burton’s Beetlejuice, he played a rare bit part as a character other than himself (as Delia’s agent). Cavett often appeared on television quiz and game shows; he appeared on What’s My Line?, To Tell the Truth, Password, The $25,000 Pyramid and made a special appearance on Wheel of Fortune in 1988 during their week of shows at Radio City Music Hall, walking on stage after someone solved the puzzle “TALK SHOW HOST DICK CAVETT”. In 1974, Cavett’s company, Daphne Productions, co-produced with Don Lipp Productions a short-lived ABC game show, The Money Maze, although Cavett’s name did not appear on the credits.

Cavett has openly discussed his bouts of clinical depression, an illness that first affected him during his freshman year at Yale. According to an interview published in a 1992 issue of People magazine, Cavett contacted Dr. Nathan Kline in 1975 seeking treatment. Kline prescribed antidepressant medication, which according to Cavett was successful in treating his depression.

Cavett’s parents taught in Comstock, Gibbon, and Grand Island, where Cavett started kindergarten at Wasmer Elementary School. Three years later, both of his parents landed teaching positions in Lincoln, Nebraska, where Cavett completed his education at Capitol, Prescott, and Irving schools and Lincoln High School. When Cavett was ten, his mother died of cancer at age 36. His father subsequently married Dorcas Deland, also a teacher, originally from Alliance, Nebraska. On September 24, 1995, Lincoln Public Schools dedicated the new Dorcas C. and Alva B. Cavett Elementary School in their honor.

In 1997 Cavett was sued by producer James Moskovitz for breach of contract after failing to show up for a nationally syndicated radio program (also called The Dick Cavett Show). Cavett’s lawyer, Melvyn Leventhal, asserted at the time that Cavett left because of a manic-depressive episode. The case was later dropped.

From November 2000 to January 2002, he played the narrator in a Broadway revival of The Rocky Horror Show. He also had a brief stint as the narrator/old man in the Broadway production of Stephen Sondheim’s Into The Woods.

Cavett is featured in the 2003 documentary From the Ashes: The Life and Times of Tick Hall about the fire that destroyed his home in Montauk, New York and his effort to rebuild it.

Cavett hosted many popular musicians, both in interview and performance, such as David Bowie, Sly Stone, Jimi Hendrix and Janis Joplin. Several of his Emmy Award nominations and one Emmy Award were for Outstanding Musical or Variety Series, and in 2005 Shout Factory released a selection of performances and interviews on a three-DVD set, The Dick Cavett Show: Rock Icons, showcasing interviews of and performances by musicians who appeared on the Dick Cavett show from 1969 to 1974.

In 2008, Cavett entered an Iraq war dispute with a New York Times blog entry criticizing General David Petraeus, stating “I can’t look at Petraeus—his uniform ornamented like a Christmas tree with honors, medals, and ribbons—without thinking of the great Mort Sahl at the peak of his brilliance.” Cavett went on to recall Sahl’s expressed contempt of General Westmoreland’s display of medals, and criticized Petraeus for not speaking in plain language.

In December 2012, for their annual birthday celebration to “The Master,” The Noel Coward Society invited Cavett as the guest celebrity to lay flowers in front of Coward’s statue at New York’s Gershwin Theatre, commemorating the 113th birthday of Sir Noel. Coward had made an appearance on Cavett’s ABC late-night television show in 1970 after having been knighted by Queen Elizabeth II in December 1969.

In January 2020, when Cavett appeared as a guest on Late Show with Stephen Colbert, Colbert stated that he was a huge admirer of Cavett, and had seen all of his talk shows. Colbert also stated, “People ask me who my influences are, and of course Johnny Carson, and of course David Letterman, but the one people don’t automatically know is what a huge influence you were on me, the way you interview people was so honest, you had such interesting and unusual guests and asked such interesting and deep questions”.