"To win at Bay Hill was always one of my goals and to win here today is a great feeling," the 44-year-old Fijian told reporters after shooting a three-under-par 67 in the final round.
He broke free from a tightly bunched leaderboard with an early four-birdie burst in five holes and could afford the luxury of three bogeys over the closing stretch before claiming his 31st PGA Tour title.
Very few of his peers could deny he was probably owed a win at Palmer's own club.
Singh made his debut at the event in 1993 when given a special invitation by tournament host Arnold Palmer and tied for second place, two shots behind winner Ben Crenshaw.
He was joint runner-up the following year, consecutive bogeys on the last two holes leaving him one stroke behind American Loren Roberts.
Eleven years later, he again had to settle for the bridesmaid spot. Level with American Kenny Perry playing the last, Singh hit his seven-iron approach into the water guarding the green before finishing two adrift with a closing 69.
When finally presented with the trophy by Palmer on the 18th green, the Fijian was congratulated by poignant words.
Singh recalled them: "First of all, Arnold said: 'Well done. It was a long time coming.' And then he said: 'I knew 20 years ago you were going to win this tournament.'
"It is rewarding. Each time before when I was in contention I either needed a par to get in the playoff or bogey, and I messed up every time.
"Today was a great feeling, but I still hate that hole," he added, referring to the 18th where he had to make an eight-foot putt to save par.
"It's not one of my favourite holes to play."
Four clear of the chasing pack with three holes to play, Singh dropped shots on 16 and 17.
"I thought: 'Here we go again. What am I doing to myself? But I then hit a very good drive on the last.
"I knew how difficult Bay Hill plays on Sundays," Singh added. "It was a good feeling to be standing on 18 knowing that you don't have to make a par to win the tournament. I could have made a bogey."