Carren started his writing career in the late 1970s and wrote stories for episodes of Switch (1978, with Barbara Luna and co-writer Peter Allan Fields), Buck Rogers in the 25th Century (1979, with Tim O'Connor and Felix Silla), Beyond Westworld (1980, with Nancy Harewood), Capitol (1982), The Powers of Matthew Star (1983, with Richard Herd, Bruce French, and director Vincent McEveety), The Twilight Zone (1985, with Carolyn Seymour), G.I. Joe (1985-1986), and Spenser: For Hire (1986-1987, starring Avery Brooks and Carolyn McCormick). For his work on Capitol, Carren received a Writers Guild of America Award nomination in 1984 in the category Daytime Serial.