He shot a 3-under 68 on Sunday to cap a one-stroke victory over Nick Price and Lonnie Nielsen in the Commerce Bank Championship.
Roberts had three second-place finishes on the Champions Tour this year, including last week to Jeff Sluman, but his 12-under 201 total gave him his eighth title on the over-50 circuit, matching his total from his PGA Tour career.
The 53-year-old Roberts earned the winners share of $240,000 from the $1.6 million purse in the event he finished second in last year.
Price matched the tournaments low round with a 6-under 65 and finished tied for second at 11-under with Nielsen, the defending champion, who had a closing 66.
Sluman (66) and Gene Jones (67) were another stroke back at the 7,072-yard Red Course at Eisenhower Park.
Roberts, who birdied No. 17 and bogeyed 18, is the fourth wire-to-wire winner in this event, joining Bruce Fleisher (1999, 2000) and Ron Streck (2005).
He led by one stroke after an opening 65 and was up by two over David Eger and Scott Simpson after a second-round 68.
After bogeying No. 1 with a three-putt for the second straight day, a birdie at the par-5 third had Roberts in a seven-way tie for the lead until Eger birdied No. 5 with a 10-foot putt to get to 10 under.
Roberts tied Eger at 11 under with a short birdie putt on No. 11, and he took the lead for good with a 4-foot birdie putt on the par-5 12th, a hole Eger bogeyed.
Price made three straight birdies starting at No. 14 to get within one shot but he parred the last two holes.
Sluman got within one of Roberts with a birdie on No. 15 from 13 feet, but he missed birdied putts on the next two holes and then bogeyed 18.
Nielsen, who finished two strokes in front of Roberts last year for his first Champions Tour win, made a 14-foot birdie putt on 17 to get within one, then left a 26-foot birdie putt just short on 18.
Minutes later, Roberts, considered one of the sports best putters, made a 29-footer on No. 17 for a two-shot lead, one he needed when he bogeyed the closing par 4.
Tim Simpson (67), Mike Goodes (68) and Scott Simpson finished at 204. Andy Bean (68), Mark McNulty (69), Fulton Allem (69) and Eger (70) were another stroke back.