Alfonso has been in the entertainment business since he was a child. While performing the star role in the Broadway musical, "The Tap Dance Kid," Michael Jackson noticed him and he was cast in one of Jackson's Pepsi commercials. He also played Ricky Schroder's best friend in the long-running sit-com Silver Spoons in the 1980s.
Alfonso is best known for his role as Carlton Banks, in the popular sit-com "The Fresh Prince of Bell Air." He played this role from 1990 to 1996. After the sit-com ended, he hosted game shows "Catch 21" on GSN and "Spell-Mageddon on ABC Family. He also directed episodes of the television comedies "Meet the Browns and "Are We There Yet?"
Alfonso was one of the celebrities on Season 19 of "Dancing with the Stars" in 2014. He won the competition. He later returned to the show as a guest judge and subbed for the host Tom Bergeron. In 2015, he was tapped to replace Tom Bergeron as the host of "America's Funniest Home Videos."
Sources: IMDB, Wikipedia