The Montrose resident, who also won the Western State Conference individual championship in April, made par in the first playoff hole before notching a birdie on the second playoff hole to move on to the event for the first time.
"It's a really big accomplishment for me," said Timpson, who won a Pacific League individual title in 2010 before helping Glendale college advance to the California Community College Championships for the first time in May. "It's always been one of my dreams to play in that event and it's basically a pro-like tour for amateurs."
Timpson fired a first-round 72 on Tuesday, though he said he encountered some difficulty with his swing. He made some adjustments prior to Wednesday's round and things clicked.
"I had no confidence with my ball striking [on Tuesday]," Timpson said. "I hit the ball much better in my second round, even though I didn't putt too well throughout the qualifier.
"What helped me was being able to drive the ball well off the tee."
Paul Misko carded a second-round score of 73 to win the event with a 141. JJ Holen finished with a two-round score of 144 to take second, followed by Mark Miller (145). The alternates will be Sean Birren (146) and Brett Silvernail (146).
Three area residents from the field of 87 also participated in the qualifier. Anton Arboleda, a La Cañada High graduate and the reigning All-Area Boys' Golfer of the Year, had a two-round score of 147 to tie for eighth. Jay Kim of La Cañada Flintridge finished with a two-round score of 148 to place 12th.
Robbie Clemente of Glendale had a first-round score of 80 before withdrawing. He finished tied for 47th.
The U.S. Amateur Public Links is one of 13 championships conducted by the United States Golf Assn. The winner of the event receives an exemption into the following years Masters and U.S. Open.
Lion Kim defeated David McDaniel, 6 and 5, to win the championship last year at Bryan Park Golf and Conference Center's Champions Course in Greensboro, N.C.