Owner of several multi-million dollar corporations, including Mister Sunshine Music, an International publishing company, and Parc Studios, which has a client list that includes the Backstreet Boys, N'Sync, Britney Spears, LFO, Mariah Carey, Linda Eder and Coolio.
He is credited with discovering and managing artists such as Lynyrd Skynyrd, Molly Hatchet, and Quiet Riot and he has managed artists such as Peter Noone of Herman's Hermits, Pat Travers, Bertie Higgins and Steven Seagal. He also managed five-time World Boxing champion Hector "Macho" Camacho.
In 2002, Armstrong and Larry R. Stessel formed Titan Entertainment Group, and the two men own Parc Records, Inc., an independent music label based in Orlando.
He is a voting member of the National Association of the Recording Arts and Sciences, which presents the Grammy Awards, and the Country Music Association.