Seth Mumy began his acting career at the age of six, appearing in a television commercial for Tide detergent. He went on to appear in a number of other television shows and films, including The Twilight Zone, The Brady Bunch, and The Rockford Files.
In 1965, Mumy was cast as Will Robinson in the original Lost in Space television series. The show was a critical and commercial success, and Mumy's performance was praised by critics.
After Lost in Space ended in 1968, Mumy continued to act in television and film. He appeared in a number of made-for-television movies and guest-starred on a number of television shows. In 1994, he was cast as Gordon Jump in the Babylon 5 television series.
Mumy has also directed several episodes of television, including Babylon 5 and Stargate SG-1.
