During the 1960s and 1970s Reid wrote and produced artists including Betty Wright, Sam & Dave, Gwen McCrae, Jimmy "Bo" Horne, Bobby Byrd, and KC & the Sunshine Band. He also recorded many of his own songs during this period, including "Nobody But You Babe".
Reid wrote sexually explicit versions of hit songs for fun but only performed them for his friends at parties or in the studio. In 1971, he along with a band of studio musicians recorded a whole album of dirty songs under the name Blowfly. The album, The Weird World of Blowfly, features Reid dressed as a low-rent supervillain on its cover. He created this alter ego to protect his career as a songwriter, and continued to perform in bizarre costumes as his Blowfly character and continued to record sexually explicit albums throughout the 1970s/80s. The albums were widely popular as "party records". The explicit version of his song "Rapp Dirty" (a.k.a. "Blowfly's Rapp [sic]") helped the album Blowfly's Party reach #26 on Billboard magazine's Black Albums chart and #82 on the Billboard Top 200 in 1980.
Blowfly's profane style earned Reid legal trouble. He was sued by songwriter Stanley Adams, who was ASCAP president at the time, for spoofing "What a Diff'rence a Day Makes" as "What a Difference a Lay Makes". Reid's own compositions have been sampled by dozens of hip hop, R&B, and electronic artists (such as Beyonce, Wu Tang Clan, DJ Quik, DMX, Method Man & Redman, Main Source, DJ Shadow, Eazy-E, RJD2, Jurassic 5, Big Daddy Kane, Mary J. Blige, Brand Nubian, and the Avalanches) but Reid has received almost no money from sampling due to signing away most of his royalties.