Paul Shaffer is a Canadian singer, composer, actor, author, comedian and multi-instrumentalist.

Shaffer began his music career in 1972 when Stephen Schwartz invited him to be the musical director for the Toronto production of Godspell, starring Victor Garber, Gilda Radner, Martin Short, Eugene Levy, Dave Thomas and Andrea Martin.

He was a member of the house band on NBC's Saturday Night Live from 1975 to 1980.

In 1977, Shaffer left Saturday Night Live for a few months to co-star with Greg Evigan in A Year at the Top, a short-lived CBS sitcom in which Shaffer and Evigan play two musicians from Idaho who relocate to Hollywood where they are regularly tempted by a famous promoter (who is actually the devil's son) to sell their souls in exchange for a year of stardom.

Beginning in 1982, Shaffer served as musical director for David Letterman's late night talk shows: as leader of "The World's Most Dangerous Band" for Late Night with David Letterman (1982–1993) on NBC, for which he also composed the theme song, and as leader of the CBS Orchestra for the Late Show with David Letterman (1993–2015) on CBS.

Shaffer was the musical director for A Very Murray Christmas, a 2015 Netflix variety special starring Bill Murray in which Shaffer also appears and performs extensively.

Shaffer wrote and performs the theme song and bridging music on Letterman's Netflix series My Next Guest Needs No Introduction with David Letterman which premiered in 2018.