He also appeared in the films National Lampoon's Christmas Vacation (1989), Suicide Kings (1997), I Know What You Did Last Summer (1997), Bookies (2003), Hancock (2008), and In Time (2011).
The play closed on February 18, 2007, with Galecki taking home a 2007 Theater World Award for his performance.
Galecki currently plays the part of Leonard Hofstadter in the CBS sitcom The Big Bang Theory, which debuted September 24, 2007.
While Sheldon's genius seems to be focused primarily in math and science, Leonard is indicated to be proficient in literature and history as well as the sciences; he is able to solve a woman's crossword puzzle in seconds, Leonard gives the answers being mostly literature based, e.g. It is also suggested that Leonard's IQ is not as high as Sheldon's; Sheldon scoffs at Leonard's whiteboard theories as common enough to be "scribbled on the wall of every men's room at MIT". Koothrappali ‧ Stephanie Barnett ‧ Lucy ‧ Mary Cooper ‧ Zack Johnson ‧ Beverly Hofstadter ‧ Mike Rostenkowski ‧ Alex Jensen ‧ Professor Proton ‧ Missy Cooper ‧ Ramona Nowitzki ‧ Dan ‧ Josh Wolowitz ‧ Dennis Kim ‧ Althea Davis ‧ Jeanie ‧ Cinnamon ‧ Mrs.
Most of the equations on Leonard and Sheldon's boards feature complex higher mathematics, such as virtual particles in QM, or series of Riemann zeta functions.
He also played the half-brother of the main characters, sisters Hope Shanowski and Faith Fairfield, in the TV sitcom Hope & Faith.
In late 2006/early 2007, Galecki starred in the Broadway play The Little Dog Laughed as Alex, a male prostitute.Galecki appeared in the first-season episode, "Stole Beer from a Golfer", of My Name is Earl as a golfer.He played a character named Trouty on TBS's sitcom My Boys.As a child, he was well known for making up long, epic stories and tales.In such situations his mother used to make him play the "quiet game" where he had to see how long he could go without talking.Galecki owns 360 acres of land in Santa Margarita, California.