Fox started his career in programming in 1979, covering eastern and mid-western television stations for D. L. Taffner, Ltd., representatives of British independent Thames, the CBC, and ABC, Australia. In 1981, he co-founded Fox/Lorber Associates, which is now part of Bob and Harvey Weinstein’s Genius Products. There he syndicated hundreds of hours of specials on behalf of HBO, Showtime, the Estate of Elvis Presley, and Saturday Night Live's Lorne Michaels. He also co-founded A&E Home Video (1989) and reconfigured and secured the first television exposure for the breakout children’s hit program, “Barney” (1991).

In 1992, Fox co-founded Unapix Entertainment, which became one of the world’s largest independent distributors of film and television programming. In 1994 he teamed with noted Canadian television innovator Moses Znaimer to start CityInteractive. From 1994 to 1998, he executive-produced over 20 hours of specials for PBS and managed the licensing of over $20 million of programming to US cable networks. In January 1999 he became CEO of myTVshop, which created unique advertising and commerce opportunities for the web sites of local television stations. In July of 2001 he launched David Fox and Associates.