Among the first such groups signed were the Paul Butterfield Blues Band from Chicago and Arthur Lee's Love from Los Angeles.

[1] Elektra wanted the Lovin' Spoonful, but they had already been signed to Kama Sutra Records in a previous production deal.

Some suggest What's Shakin' started as The Electric Blues Project, a follow-up to the 1964 compilation;[3] however, Elektra founder Jac Holzman has stated "it was simply unreleased material that was available to us".

Joe Boyd, who had been sent to London to open a field office for Elektra, was tasked with finding a suitable band for his first assignment.

[5] Jones, who played harmonica and sang harmony, brought Manfred Mann bandmate Jack Bruce on bass, recruited the Spencer Davis Group's vocalist Steve Winwood and drummer Peter York, John Mayall & the Bluesbreakers's and former Yardbird's guitarist Eric Clapton, and Ben Palmer, a blues pianist friend of Jones and Clapton.

Jones chose "I Want to Know" (his own composition, although credited to his wife, Sheila MacLeod) and Winwood selected "Steppin' Out".

[5][9] According to Boyd, Clapton wanted to record Albert King's "Crosscut Saw", but Boyd suggested "Standing at the Crossroads" (a version of Robert Johnson's "Cross Road Blues" recorded by Elmore James); Clapton then suggested Johnson's "Traveling Riverside Blues".

[13] Most of the songs from What's Shakin' later were included on compilations and career retrospectives by Al Kooper, Eric Clapton, Steve Winwood, and John Sebastian/Lovin' Spoonful.

[4] Writing for AllMusic decades after the original LP release, Unterberger gave What's Shakin' a rating of three out of five stars.