Post's first credited work in music was cutting demos using two singing sisters, Terry and Carol Fischer.

[citation needed] Post also provided early guidance for the garage rock band The Outcasts while in recruit training in San Antonio, Texas.

[4] He won his first of five Grammy Awards at age 23 for Best Instrumental Arrangement on Mason Williams' "Classical Gas",[5] a number 2 hit song in 1968.

[13] At the peak of his career, Post was the go-to composer for all of the series created by Donald P. Bellisario, Steven Bochco, Stephen J. Cannell and Dick Wolf.

; NewsRadio; Profit; Quantum Leap; Renegade; Riptide; Silk Stalkings; Stingray; Tales of the Gold Monkey; Tenspeed and Brown Shoe; The White Shadow; Wiseguy; the BBC series Roughnecks; and Philly.

[citation needed] In 2014, Post composed the score for the fake TV pilot Caged Heat in the All Hail the King short film for Marvel Studios.

The CD contained several of his well-known themes, featuring NYPD Blue and also including Law & Order, Silk Stalkings and Renegade.

In 1989, Broadcast Music, Inc. Foundation and Mike Post established The Pete Carpenter Fellowship in memory of the late Pete Carpenter, who was Post’s co-composer of television scores and themes including The Rockford Files (for which they won a Grammy), Hunter, Riptide, Hardcastle and McCormick, Magnum, P.I.

The Pete Carpenter Fellowship is an annual, competitive residency for aspiring television, film and video game composers.