He became famous as the longest-serving host of Late Night, hosting the NBC show for 16 years from 1993 to 2009.

Conan O'Brien was born on April 18, 1963, in Brookline, Massachusetts. Standing at 6 feet 4 inches tall, this Aries comedian became one of television's most influential late-night hosts through a career spanning nearly 30 years. He wrote for Saturday Night Live and The Simpsons before hosting Late Night with Conan O'Brien (1993-2009), The Tonight Show with Conan O'Brien (2009-2010), and Conan on TBS (2010-2021). After leaving traditional television, he launched the successful podcast Conan O'Brien Needs a Friend in 2018 and the HBO Max travel series Conan O'Brien Must Go in 2024. He received the Mark Twain Prize for American Humor in 2025 and was inducted into the Television Academy Hall of Fame the same year.

He grew up in Brookline, Massachusetts, in an Irish Catholic family as the third of six children. His father, Thomas Francis O'Brien, was a physician and professor at Harvard Medical School, while his mother, Ruth O'Brien, was an attorney at Ropes & Gray. He graduated as valedictorian from Brookline High School in 1981, then attended Harvard University where he served as president of the Harvard Lampoon and graduated magna cum laude with a degree in history and literature in 1985. After graduation, he moved to Los Angeles and worked as a writer for HBO's Not Necessarily the News before joining Saturday Night Live's writing staff in 1988.

He married Liza Powel O'Brien in 2002 after meeting her on his show in 2000 when she appeared in an audience skit. The couple has two children together, daughter Neve and son Beckett. He maintains strong ties to his Irish heritage and has visited County Kerry, Ireland, where his ancestors originated. Outside of comedy, he plays guitar and maintains a collection of vintage cars.