But it is not unusual for qualifiers to do well in the U.S. Open. Many of the qualifiers are top professionals, after all. In 2005, for example, Jason Gore advanced through both local and sectional qualifying and played in the final pairing of the final round.
Moreover, 2005 champion Michael Campbell came out of sectional qualifying (he was exempt from local qualifying) to win the tournament.
So there's one answer to the question: the last golfer to win the U.S. Open after going through sectional qualifying was Campbell in 2005. And prior to Campbell's win, the last previous U.S. Open winner to go through sectional qualifying was Steve Jones in 1996.
The last golfer to win the tournament after going through both stages of qualifying - local and section - was Orville Moody in 1969. Interestingly, while the "Sarge," as he was called, played on the PGA Tour for many years, that U.S. Open win was the only victory of his career.

