Stolen from Wikipedia:

Gregory Everett Proops (born October 3, 1959, in Phoenix, Arizona) is an American actor and stand-up comedian, and works largely in Europe as a comic and improviser.

Raised in San Francisco, Proops studied improvisation and acting at San Francisco State University. After graduation, he joined an improv group with Mike McShane, which proved to be his ticket to stardom. Both Proops and McShane impressed producers Dan Patterson and Mark Leveson, who put them on their show, Whose Line Is It Anyway?.

Proops has performed his stand-up act across Europe and in New Zealand. However, he remains best-known for appearances on Whose Line?, including both the US and UK versions. He reprised this role in 2004’s Drew Carey’s Green Screen Show, a show similar to Whose Line. His other credits include hosting Space Cadets, a mid-1990s science-fiction comedy gameshow on Channel 4 in the UK, which also featured Craig Charles (Lister from Red Dwarf) and Bill Bailey, and appearances on BBC2’s Mock the Week. He appeared as a panelist on the 2000 revival of To Tell the Truth. Proops also hosted two game shows: VS. in 1999 Rendez-View in 2001.

In addition to his stand-up and improv acts, Proops has done voice work in various films and TV shows, including Star Wars: Episode I, the miniseries Stripperella with Pamela Anderson, and the children’s show Bob the Builder. He also hosts a bi-weekly radio program, and a nightclub-atmosphere talk show at the Largo in Hollywood. He lists McShane and Colin Mochrie as among his best friends.

Proops and his wife of 11 years, Jennifer, currently live in Los Angeles.