Hartman worked as a songwriter, producer, and collaborated with such artists as the Plasmatics (Hartman produced a demo version of "Coup d'Etat" in 1982, which was released as "Coup de Grace" in 2000), Nona Hendryx (she co-wrote the song "Electricity" with Hartman, which was featured on his 1984 "I Can Dream About You" album), James Brown ("Gravity"; 1986), Steve Winwood (Hartman provided backing vocals on "The Finer Things", which was featured on Winwood's 1986 album "Back in the High Life"), Time Bandits ("Can't Wait for Another World", 1987; co-produced with Midnight), Paul King ("Joy"; 1987), Tina Turner ("Foreign Affair"; 1989), Joe Cocker ("Unchain My Heart" and "One Night of Sin"; 1987 and 1989 respectively), Holly Johnson ("Blast"; 1989), Living in a Box ("Gatecrashing"; 1989), Dusty Springfield ("Reputation"; 1990), Tom Robinson ("We Never Had It So Good" - later re-released as "Blood Brother"; 1990), and Bonnie Tyler ("Bitterblue"; 1991). Hartman produced and co-wrote "Living in America", a No. 4 hit for James Brown which appeared on the soundtrack of the feature film "Rocky IV" (1985). The song was the last of Brown's 44 hit recordings to appear on the Billboard Top 40 charts. The track also appeared on the Hartman produced album "Gravity". In 1987, Hartman and Charlie Midnight were nominated for a Grammy Award for Best R&B Song. Brown won a Grammy Award for Best Male R&B Vocal Performance.