In 2007, Johnny began dating his The Big Bang Theory co-star, Kaley Cuoco, an American actress. They began dating soon after the start of this series. They dated each other for the next two years and they finally broke up at the end of 2009. Their separation was amicable.
As a child, Johnny was an expert in making long stories and tales. He also used to play a quiet game with his mother. His dream was acting and he made his acting debut in 1987 starring the role of Matt Kowalski in the movie, Time Out for Dad. The following year, he appeared in the movie, Murder Ordained. His breakthrough role came in 1992 after he began appearing in the television series Roseanne. He has also been appearing in the television series, The Big Bang Theory since 2007. For this role in this series, he earned a salary of $1,000,000 per episode. His net worth is said to be around $7 million.