At the 2012 U.S. Open, Harrington was in contention to win a fourth major championship, when rounds of 74-70-71 on the first three days got him into contention on Sunday. After bogeying two of the first six holes, Harrington preceded to play the stretch from hole 7–17 in 5-under-par to find himself two behind the leader. Needing a birdie at the last to finish ahead of the clubhouse leader Michael Thompson, Harrington took the pin on at the 18th and found a plugged lie in the greenside bunker, which resulted in a bogey finish at 3-over-par. Ultimately this did not cost him the championship as he finished two shots behind Webb Simpson on 1-over-par. Harrington later stated that he thought he had to birdie the last to get to 1-over-par as the reason for taking such an aggressive line on the 18th. He eventually finished in a tie for fourth place, which represented his best showing at a U.S. Open.