One of the greatest tennis players of all time, John McEnroe is as famous for his on-court disputes with officials as for his dozens of tournament titles. He's now a tennis commentator on NBC and with the BBC.

Born in Germany, McEnroe grew up in Queens and began playing tennis at the tender age of eight. With a few national junior tournaments under his belt, he, as an amateur, won his first major event in the French Open mixed doubles with Mary Carillo (and later became a fellow sportscaster with him on NBC) and qualified for Wimbledon to play against Jimmy Connors in a match that was called one of the best performances by an amateur in tennis history. He quickly signed his first endorsement deal and won his first singles Grand Slam title two years later at the US Open. He's perhaps best known for his rivalry with Bjorn Borg and their controversy-laden Wimbledon appearances in 1980 and 1981, when McEnroe's refrain of "You cannot be serious," later became the title of his autobiography (and nearly got him tossed from the tournament). After a few painful losses, McEnroe took a brief tennis sabbatical in 1986 but returned in even worse form and more fines for yelling at referees, causing speculation of drug abuse (he later admitted to using cocaine at the time). Although he retired at a low point in 1992, McEnroe might just be one of sport's most notable bad boys done good, becoming one of NBC's most popular commentators and poking fun at his former rageful personality with cameos on shows like 30 Rock and Curb Your Enthusiasm.

As fraught as his tennis career was, McEnroe's marriage to actress Tatum O'Neal was even more dramatic. The pair wed during McEnroe's 1986 sabbatical and had three children, but split in 1992. Following the divorce, O'Neal's addiction to heroin resurfaced, and McEnroe gained custody of the children. These days he's married to rock singer Patty Smyth (but not that Patti Smith). [Image via Getty]