A day after matching a Champions Tour record with a 10-under-par 60, Thorpe carded a 67 to defeat Gilder by a stroke at Eisenhower Park, the new home for this event.
Thorpe coughed up a two-stroke advantage early Sunday, but birdied the par-3 16th hole to catch Gilder and the par-5 17th to grab the lead himself. Both parred the 18th, giving Thorpe the victory.
The 54-year-old Thorpe finished the 54-hole event at 15-under 195, three shots lower than the tournament record Bruce Fleisher set three years ago.
Thorpe earned his sixth career Champions Tour crown and first since last year's Tradition. He will attempt to defend his title at the Tradition -- the season's final senior major -- in two weeks.