A native of the Washington, D.C. area, Simpson broadcast Atlantic Coast Conference basketball games in the early 1960s and worked as a sports reporter at WRC-TV. Eventually he would broadcast many sports at NBC, including football, basketball, baseball, tennis, and golf. For much of the 1960s and 1970s he was generally considered the network's number two play-by-play announcer, behind only Curt Gowdy. His work on American Football League and later American Football Conference games for NBC is perhaps what he is best remembered for.

In 1979, the fledgling ESPN cable sports network brought Simpson on board to provide some needed credibility with sports fans. Simpson broadcast the first NCAA basketball game the network televised, with flamboyant Dick Vitale as the color man. Vitale credits Simpson with helping him develop as a sportscaster. Simpson also called USFL and College World Series games for ESPN.

After his sportscasting days Simpson retired to St. Croix, Virgin Islands. Among other firsts he was the initial U.S. sportscaster to appear live via satellite from Asia, and he was involved in the first American sportscast using instant replay technology. In 2005, ESPN brought Simpson back from retirement to do play-by-play for a series of college basketball games in a "turn back the clock" format on the ESPN Classic network.