The 57-year-old Triplett also won the PGA Tour Champions event in 2012 and 2013. He has eight senior victories, also winning a playoff in March in the Hoag Classic down the coast in Newport Beach.
Playing four groups ahead of Andrade, Triplett birdied the 18th in regulation for a 5-under 67 and 9-uner 206 total. Andrade also closed with a birdie, holing a 7-footer after hitting his second shot through the green.
The 55-year-old Andrade missed a 20-foot birdie try before Triplett holed the winning putt in the event that pairs tour players with juniors from The First Tee programs around the country.
Second-round leader Steve Flesch had a 75 to tie for ninth at 5 under.