American actor Johnny Galecki was born on April 30, 1975 in Bree, Belgium. He got his American citizenship because both his parents are American; his father was part of the U.S. Air Force and was stationed in Belgium at the time of his birth. His family moved back to Oak Park, Illinois when he was three years old. He began acting at a young age, appearing in stage productions as early as age 7. When he was just 11 years old, he was already nominated for a Joseph Jefferson Award for his role in the play The Member of the Wedding.
Galecki started acting for the screen in 1987, and made the rounds of television movies and guest roles in regular shows. In 1992, he joined the cast of the successful sitcom Roseanne; he played the role of David Healy, the soft-spoken and art-inclined boyfriend, and later husband, of middle child Darlene Connor (Sara Gilbert). He played the role until the show’s finale in 1997. He afterwards appeared in several films, including Bean, Suicide Kings, I Know What You Did Last Summer, The Opposite of Sex, Vanilla Sky and Bookies.
Galecki returned to television screens in the early 2000s, playing recurring roles in the comedies My Boys and Hope & Faith. In 2007, he joined the cast of the sitcom The Big Bang Theory, which reunited him with his Roseanne co-star Sara Gilbert. He played the role of Leonard Hofstadter, an experimental physicist from the California Institute of Technology. Also proficient in literature and history unlike his friend Sheldon (Jim Parsons), he has a deep crush on new neighbor Penny (Kaley Cuoco), and does everything he can to get her attention.
Galecki also continued to appear on stage, notably appearing in the Broadway play The Little Dog Laughed, where he was required to do full frontal nudity, as he played a male prostitute.