By the time he was 12, Avalon began making appearances on U.S. television for his trumpet prowess, and as a teenager, played with Bobby Rydell in a band known as Rocco and the Saints. In 1959, his songs "Venus" and "Why" both went to number one on Billboard magazine's Hot 100. Indeed, "Why" was the last #1 hit of the 1950s. Avalon had 31 charted Billboard U.S. singles during his career from 1958 to late 1962, with most of the hits written and/or produced by Bob Marcucci, head of Chancellor Records. In 1964, he was one of the artists to help open the Circle Star Theater in San Carlos, CA.
In his acting, he was best known for his starring roles in the teenage Beach Party film genre, though he also had straight dramatic parts in films such as The Alamo as well as Voyage to the Bottom of the Sea. Avalon also appeared in nearly two-dozen TV episodes, including a role in "The Patty Duke Show" titled "A Foggy Day in Brooklyn Heights," appearing as himself (Frankie Avalon). Later, he became the U.S. national television spokesperson for Sonic Drive-In.
The 1980 film The Idolmaker, written by Gene Kirkwood and directed by Taylor Hackford, was a thinly-disguised biography of Frankie Avalon (called "Tommy Dee" in the film) as well as 1950s teenage star Fabian (called "Caesare" in the film), as well as songwriter/producer Marcucci (called "Vinnie Vacarri" in the film). In the movie version, Tommy Dee clashes frequently with the producer and younger singer Caesare, whom he feels threatens his career as an upstart. Eventually, both "Dee" and "Caesare" quit the label, but both their record careers collapse, just as the British Invasion begins. The real-life Fabian threatened a lawsuit at the time of the film's release, though the filmmakers insisted that the film presented only fictional characters (though Marcucci was a paid consultant on the film). Avalon later denied most of the movie's events in interviews.
Frankie Avalon married Kathryn Diebel on January 19, 1963. She was a former beauty pageant winner, and Avalon met her while playing cards at a friend's house. He told his friend that Kay was the girl he was going to marry. His agent warned Avalon not to marry, as it would spoil his teen idol mystique, but Avalon ignored his advice. Still together, the couple has eight children--in order of age, they are Frankie Jr., Tony, Dina, Laura, Joseph, Nicolas, Kathryn and Carla. They also have 10 grandchildren. Frankie Jr. is a drummer and Tony, the second oldest son, currently plays guitar and teaches at the Paul Green School of Rock; both still tour and perform with their father.
In 1987 Avalon and Annette Funicello returned to the movies, with the aptly titled Back to the Beach. Not long afterwards, Funicello was diagnosed with MS, and retired from acting.
He regularly guest stars in stage productions of Grease in the role of Teen Angel (a role he played in the popular 1978 film adaptation) and Tony n' Tina's Wedding as a characterized version of himself. Additionally, in 2007, he performed the song "Beauty School Dropout" with the four remaining female contenders (Kathleen Monteleone, Allie Schulz, Ashley Spencer, and winner Laura Osnes) for the role of Sandy on the NBC television reality show Grease: You're the One that I Want!. Also, his first son, Frank B Avalon Jr., frequently plays the drums on tour with his father.