Philip Alfred Mickelson (born June 16, 1970), nicknamed Lefty, is an American professional golfer. He has won 43 events on the PGA Tour, including five major championships: three Masters titles (2004, 2006, 2010), a PGA Championship (2005), and an Open Championship (2013). Mickelson is one of 16 players in the history of golf to win at least three of the four majors. He has won every major except the U.S. Open, where he has finished runner-up a record six times.

Mickelson attended Arizona State University in Tempe on a golf scholarship and 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. With three individual NCAA championships, he shares the record for most individual NCAA championships alongside Ben Crenshaw. Mickelson also led the Sun Devils to the NCAA team title in 1990. Over the course of his collegiate career, he won 16 tournaments.  Mickelson was the second collegiate golfer to earn first-team All-American honors all four years. In 1990, he also became the first with a left-handed swing to win the U.S. Amateur title. Mickelson secured perhaps his greatest achievement as an amateur in January 1991, winning his first PGA Tour event, the Northern Telecom Open, in Tucson. At age 20, he was only the sixth amateur to win a tour event and the first in over five years after Scott Verplank at the Western Open in August 1985. Other players to accomplish this feat include Doug Sanders (1956 Canadian Open) and Gene Littler (1954 San Diego Open). With five holes remaining, Mickelson led by a stroke, but made a triple-bogey and was then three behind. The leaders ahead of him then stumbled, and he birdied 16 and 18 to win by a stroke. To date, it is the most recent win by an amateur at a PGA Tour event.  That April, Mickelson was the low amateur at the Masters Tournament in Augusta, Georgia. With his two-year PGA Tour exemption from the Tucson win, he played in several tour events in 1992 while an amateur but failed to make a cut.Answer this question using a quote from the following article:

what did he do after college
his first PGA Tour event,