In 2010, Mickelson won the Masters Tournament on April 11 with a 16-under-par performance, giving him a three-stroke win over Lee Westwood. The win marked the third Masters victory for Mickelson and his fourth major championship overall. Critical to Mickelson's win was a dramatic run in the third round on Saturday in which Mickelson, trailing leader Westwood by five strokes as he prepared his approach shot to the 13th green, proceeded to make eagle, then to hole-out for eagle from 141 yards at the next hole, the par 4 14th, then on the next, the par 5 15th, to miss eagle from 81 yards by mere inches. After tapping in for birdie at 15, Mickelson, at −12, led Westwood, at −11, who had bogeyed hole 12 and failed to capitalize on the par 5 13th, settling for par.
Although ranked second on the PGA Tour's all-time money list of tournament prize money won, Mickelson earns far more from endorsements than from prize money. According to one estimate of 2011 earnings (comprising salary, winnings, bonuses, endorsements and appearances) Mickelson was then the second-highest paid athlete in the United States, earning an income of over $62 million, $53 million of which came from endorsements. Major companies which Mickelson currently endorses are KPMG, ExxonMobil (Mickelson and wife Amy started a teacher sponsorship fund with the company), Rolex, Workday, Inc., Callaway Golf and Mizzen+Main. He has been previously sponsored by Titleist, Bearing Point, Barclays, and Ford. After being diagnosed with psoriatic arthritis in 2010, Mickelson was treated with Enbrel and began endorsing the drug.