Philip Alfred Mickelson (born June 16, 1970) is an American professional golfer. He has won three major championships and a total of 37 events on the PGA Tour. He has reached a career high world ranking of 2nd in multiple years. He is nicknamed "Lefty" for his left-handed swing, even though he is otherwise right-handed.

Mickelson was born in San Diego, California and raised there and in Arizona. Although right-handed otherwise, he swings with his left hand, as he learned by watching his right-handed father swing and mirroring it. He graduated from the University of San Diego High School in 1988, then attended Arizona State on a golf scholarship, where he graduated in 1992. During his time at Arizona State, he became the face of amateur golf in the United States, capturing three NCAA individual championships and three Haskins Awards (1990, 1991, 1992) as the outstanding collegiate golfer. He was the second collegiate golfer to earn first-team All-American honors all four years. In addition, in 1990, he became the first left-hander to win the U.S. Amateur title. Perhaps his greatest achievement, though, came in 1991 when he won his first PGA Tour tournament, the Northern Telecom Open. He did so as an amateur, becoming only the fourth in PGA history to accomplish this feat and the first since Scott Verplank, who won the 1985 Western Open in Chicago.

Mickelson continued to win many PGA Tour tournaments, including the Byron Nelson Golf Classic and the World Series of Golf in 1996, the AT&T Pebble Beach National Pro-Am in 1998, the Colonial National Invitation in 2000 and the Greater Hartford Open in 2001 and again in 2002. He also won the Buick Invitational in 2000, defeating Tiger Woods and ending his streak of consecutive tournament victories at six. After his win, Mickelson said, "I didn't want to be the bad guy. I wasn't trying to end the streak per se. I was just trying to win the golf tournament." Mickelson also shot a round of 59 at the PGA Grand Slam of Golf at Poipu Bay Golf Course on November 24, 2004. Mickelson was known for his powerful full swing but even more so for his sweet short game, most of all his daring "Phil flop" shot in which a big swing with a high-lofted wedge against a tight lie flies a ball high into the air for a short distance.