Since its first season in 1970, Cerf has played a significant role in the creation and production of the Sesame Street television program, most notably as a regular contributor of music and lyrics, and as the producer of many of its music albums. In the process, he has won two Grammy Awards and three Emmy Awards for songwriting and music production. Since writing and performing his first song for Sesame Street, "Count It Higher" (1972), Cerf has written or co-written over 200 songs featured on the program, including "Put Down the Duckie," "The Word Is No," "Dance Myself to Sleep," "Monster in the Mirror," and such notable parody songs as "Born To Add," "Letter B," Wet Paint and "Furry Happy Monsters." Cerf also played a pivotal role in the ongoing funding of Sesame Street, founding and serving as the original editor-in-chief of Sesame Workshop's books, records, and toys division.

In addition to his contributions to Sesame Street, Cerf’s musical material has appeared on Saturday Night Live, The National Lampoon Radio Hour, The Electric Company, Square One Television, Between the Lions, and in numerous Muppet productions, and his songs have been performed by such stars as Paul Simon, Ray Charles, Johnny Cash, R.E.M., James Taylor, Tony Bennett, Dixie Chicks, Tracy Chapman, Carol Channing, Randy Travis, The Four Tops, Melissa Etheridge, Smokey Robinson, Bonnie Raitt, Wynton Marsalis, Little Richard, B.B. King, Jimmy Buffett, Bart Simpson, and the Metropolitan Opera's José Carreras—not to mention the blond, curly-haired Muppet character from Sesame Street who is his namesake and the lead singer of the rock group "Chrissy and the Alphabeats."

Before joining Sesame Street, Cerf spent eight years as a senior editor at Random House (co-founded by his father in 1927), where he worked with such diverse authors as George Plimpton, Andy Warhol, Abbie Hoffman, Ray Bradbury, Richard Fariña, and Dr. Seuss. In 1993, Cerf renewed his ties to Random House when he assumed the role of Chairman of the Modern Library's Board of Advisors.

One of Christopher Cerf's best-known projects was the editing and production of Marlo Thomas & Friends' Free To Be...A Family book, album and TV special. The book reached #1 on The New York Times bestseller list within a week of its publication in 1987, and the show received a prime-time Emmy as the year's outstanding children's special.

Cerf and Thomas recently collaborated again, co-editing and co-producing All Year Long, a book and CD about generosity and sharing (and their polar opposites, selfishness and thoughtlessness). Royalties from the project, for which Thomas and Cerf won a 2006 Grammy Award, go to St. Jude Children's Research Hospital, founded by Thomas’s father, Danny Thomas, in 1962.

Currently, Cerf serves as Executive Producer, and Music and Audio Producer, of Between the Lions, the children's literacy series that his company, Sirius Thinking, Ltd., created for PBS. Between the Lions has twice won the Television Critics’ Award as the nation’s outstanding children’s television program, and, in its six seasons on the air, the show has amassed six Emmy Awards. (In 2006, Between the Lions was nominated for three more Emmys, including Outstanding Children’s Show.) In two independent studies, conducted by the University of Kansas and Mississippi State University, the program has also demonstrated success in helping kids — including those at the highest risk of literacy failure — to learn how to read.

Along with Between the Lions, Cerf continues to cement his role in the history of children's educational programming by producing fun educational shows for children. Cerf is currently the co-Creator (with Norman Stiles and Louise Gikow), Executive Producer and Writer of the new PBS Kids show Lomax, the Hound of Music. The show, which debuted in the winter of 2008, is a new children's series featuring "a good-natured, melody-obsessed puppet pooch named Lomax, his fluffy feline sidekick Delta, and their human companion, Amy, on a tune-filled train ride crisscrossing the musical landscape of America. With the help - and full participation - of real kids on the train, on location, and the viewers at home, Lomax and his friends doggedly pursue their mutual passion: tracking down the wonderful songs that form the heart of our nation's diverse musical heritage."

In addition to being fun for the whole family, the show has true educational credentials. Aware that many American children do not receive any formal musical education, Cerf, Stiles and Gikow based Lomax on the music education curriculum created by the music educator John Feierabend, Ph.D. Feierabend's curriculum has been extensively researched and shown to increase children's musical ability and intelligence. It includes appearances by music notables such as Larry Campbell and Tom Chapin.

The show is currently in its first season and raising funds to produce a second season as soon as possible.

Christopher Cerf is perhaps best known to the general public for his work as an author and satirist. In 1970, he helped launch the National Lampoon, serving as a Contributing Editor from its first issue until the mid-1970s, and in 1978, he co-conceived and co-edited with Tony Hendra, George Plimpton and Rusty Unger the journalistic parody Not the New York Times.

The Experts Speak, the "compendium of authoritative misinformation" that Cerf co-authored with Victor Navasky in 1984, has recently been reissued. In 1986, Cerf collaborated with National Lampoon colleague Henry Beard on The Pentagon Catalog: Ordinary Products at Extraordinary Prices, which offered readers the historic opportunity to obtain a free hex nut—valued at $2,043 by the McDonnell Douglas Corporation—with every copy they purchased. (The book has a die-cut hole in its front cover and first few pages: the book was sold in clear plastic shrink wrap with a steel hex nut inside this hole, slightly less than flush with the cover. The shrink wrap displayed the hex nut and prevented it from falling out before the book was purchased.) The Official Politically Correct Dictionary, also written with Beard, first appeared in 1992.

In 2008, to commemorate the fifth anniversary of George W. Bush's victory speech aboard the U.S.S. Lincoln, Cerf again collaborated with Victor Navasky to produce Mission Accomplished! based on America's military presence in Iraq.

On 9 December 2008, the Associated Press reported that various musicians were coordinating their objections to the use of their music as a technique for softening up captives.The songs used were primarily Heavy Metal, but also included songs from Sesame Street. The Associated Press reported that Cerf "...was horrified to learn songs from the children's TV show were used in interrogations."