In 1956, Walt Disney decided to start his own record label and hired jazz musician Salvador "Tutti" Camarata to form and run Disneyland Records. The label served as an outlet for all music created for Disney's movies and television shows, but also had a few independent releases. In 1959 Disney formed Buena Vista Records to produce those independent releases separately.
One of Buena Vista's first releases was the single Lost In a Fog, by Camarata's own Tutti's Trumpets / Camarata Strings. The B-side was Toot Sweet, a jazzy instrumental composed by a frequent Camarata collaborator, 19-year-old Paul Anka.
Around that time, Annette Funicello was ready to transition from The Mickey Mouse Club to Disney's teen movies. To help transform her image, she decided to release an album of love songs, and asked Camarata to produce it. Camarata enlisted Anka, who was publicly dating Funicello at the time, to write the songs, and the album was thus entitled, Annette Sings Anka. One of the songs on the album, It's Really Love, was a reworked version of Toot Sweet, to which Anka had added lyrics.
Hollywood cranked out plenty of teen movies during the 1950s, and so did studios in Europe. One of the European productions, a 1959 French film named Faibles Feemes (starring up-and-comer Alain Delon), needed a song sung by a male teen heartthrob to suit the storyline. Anka recorded his own version of It's Really Love, and the song appeared in the film.
So, Toot Sweet began life as a humble B-side, but then helped propel Annette Funicello to stardom and later became an international hit. But this little song was not done yet.
Not by a long shot.
Listen to the original Toot Sweet, by Tutti's Trumpets / Camarata Strings:
A bit familiar? Here's It's Really Love, by Annette Funicello:
And here's Anka's cover of It's Really Love:
Yes, this is the song you know as Johnny's Theme, which opened The Tonight Show during Johnny Carson's 30-year tenure as host, from 1962 to 1992:
Carson, a fan of jazz, had worked with Anka in England on a television special, An Evening with Paul Anka, in 1961. When they happened to meet up again in New York the following year, Carson mentioned that he was taking over as permanent host of The Tonight Show in October and needed a theme song. A few weeks later, Anka came up with a new instrumental arrangement of It's Really Love and sent a demo tape to Carson.
It was love at first listen.
One last tidbit: Anka generously offered Carson the opportunity to rewrite the song's lyrics (even though no lyrics were ever used in the show) so that Carson would share the songwriting credit with Anka and thus share in the royalties every time the song was played. On average, Anka and Carson earned $200,000 each per year in royalties from Johnny's Theme.
Sweet? Darn tootin'.
Attribution note: In addition to the sources linked in the essay, material was gathered from this Internet Archive article about the evolution of Johnny's Theme and this Wikipedia article about Salvador Camarata.