Penny is a fictional character on the CBS sitcom, The Big Bang Theory, portrayed by actress Kaley Cuoco. She is the primary female character in the series. The Big Bang Theory is an American sitcom created by Chuck Lorre and Bill Prady, both of whom serve as executive producers on the show along with Steven Molaro. If you're still wondering what Penny's last name is on The Big Bang Theory, you're not the only one. Even the cast hasn't been clued in about Kaley Cuoco. What happens when The Big Bang Theory takes on Star Trek? BAZINGA!™ Penny joins the crew of the U.S.S. Enterprise! Dressed in her red Operations uniform from Star. Scene From Season 7, Episode 4 All Copyrights Go To Their Respective Owners. Image features The Big Bang Theory stars Jim Parsons and Kaley Cuoco (Ã?©2014 CBS Broadcasting, Inc. All Rights Reserved) Penny's father Wyatt with Leonard. No family name has been mentioned as of 2015 when she took the last name of her husband, Leonard Hofstadter. Never miss The Big Bang Theory! Find out where and when you can watch the show on TV or online, get the best prices for DVDs and find details about the cast and crew.