Written and first recorded (as “Leavin’ It All Up to You”) by Don & Dewey (1957).
Hit versions by Dale & Grace (US #1 1963), Donny & Marie (US #4 1974).
Also recorded by Linda Ronstadt (1970).
From the wiki: “‘I’m Leaving It All Up to You’ was written and first recorded by the Rock ‘n’ roll and Doo-wop duo Don & Dewey in 1957. Don & Dewey were Don ‘Sugarcane’ Harris and Dewey Terry, both of Pasadena, California. Both Don and Dewey played guitar, with Dewey often doubling on keyboards. When not playing guitar or bass, Don occasionally played the electric violin, a skill for which he subsequently became well known under the name of ‘Sugarcane’ Harris. ‘Wrecking Crew’ drummer Earl Palmer played frequently on their sessions. (In 1970, Harris re-emerged from semi-retirement to a wider rock audience, playing violin on the Hot Rats solo album by Frank Zappa, with Captain Beefheart (vocals) on ‘Willie The Pimp’ and on the lengthy instrumental jam, ‘The Gumbo Variations’. Harris went on to play on many more solo Zappa, and The Mothers of Invention albums.
“Although Don & Dewey did not have any hits of their own, several of the songs that they wrote and/or recorded would appear on the charts later, performed by other artists. Most famously, ‘I’m Leaving It Up to You’ became a #1 hit for Dale & Grace in 1963. It was the #1 song when President John F. Kennedy was assassinated in Dallas, Texas, in November 1963. Dale & Grace were in Dallas on the day of the assassination and were scheduled to perform that night as part of Dick Clark’s ‘Caravan of Stars’ (with Bobby Rydell, Jimmy Clanton, and Brian Hyland), and just moments before the assassination had waved to the president’s passing motorcade from a vantage point near their hotel.”