<P> It is possible that Leonard is based on the show's co-creator, Bill Prady, back when he was a computer programmer . Leonard has been described as the straight man of the series . Penny (Kaley Cuoco) is Leonard's next - door neighbor and main love interest, and the teasing of romance between the two of them is a major force driving the series . In "The Gorilla Dissolution", they finally become engaged, marrying in Las Vegas at the beginning of season 9 . </P> <P> Leonard is named after actor / producer Sheldon Leonard, and Nobel Prize in Physics Laureate Robert Hofstadter . Johnny Galecki was originally asked to play the role of Sheldon Cooper, but thought he would be "better suited" for the character of Leonard . Leonard is one of four characters to appear in every episode of the series, along with Sheldon, Howard Wolowitz and Raj Koothrappali . </P> <P> Originally from New Jersey and a graduate of Princeton University, Leonard works as a Caltech experimental physicist, mainly working with lasers, and shares an apartment with colleague Sheldon Cooper in Pasadena, California . He is usually seen wearing his characteristic black thick - framed glasses, low - cut black Converse All Stars sneakers, pastel hoodies or neutral - colored sweat jackets (i.e. jackets with integrated hoodies) or a combination of the two, brown or red trousers (or, less frequently, jeans), and physics - themed T - shirts . His various girlfriends have tried to change his outfits: Penny had no success while Stephanie got him to wear dress shirts and sweaters (which he found uncomfortable), and Priya got him to briefly switch to dress shirts, waistcoats and dark slacks; he reverted to his original outfits after she left for India, but started eschewing his hoodies in favor of button - down shirts and non-hooded jackets towards the end of the seventh season, a trend that continued into successive seasons . </P> <P> Although Leonard feels at home with his geek colleagues, he wants to be more social . Among the main characters, he has little to no difficulty interacting with "non-geek" individuals . He is instantly captivated by Penny, and from the beginning sets out to date her . </P>

What is leonard's job on big bang theory