The 16-time world champion, 56, raced into a 8-3 lead and held off a brief fightback from Scotland's Wright to reach the fourth interval 13-7 up.
Taylor then won four straight legs, with Wright taking one in consolation before the Englishman sealed victory.
"This has capped everything off for me," Taylor told Sky Sports.
The former world number one is set to stop touring after the 2018 World Championship, which ends in January.
"This couldn't have come at a better time - it's a bonus for me," added Taylor.
"I'm done now, my back is in half, my legs are killing me - I'm doing everything I can to prolong my career so to win a major now at my age is fantastic."
Taylor averaged 104.24 in a vintage performance in front of a partisan crowd at the Winter Gardens.
After losing in the second round of the inaugural World Matchplay in 1994, Taylor has now won 16 of the 23 subsequent tournaments.
Compatriot Rod Harrington and Dutchman Michael van Gerwen are the only other players to win multiple World Matchplay titles, with two each.
"I'll miss this place tremendously - I've loved it since I first walked through the door," said Taylor.
In victory, Taylor made seven 180 maximums in the final and hit 56% of checkouts as Wright struggled to hit doubles early on.
It capped a fine run in this year's tournament, with Taylor easing past two-time defending champion Van Gerwen and two-time world champion Adrian Lewis en route to the final.
Phil Taylor thrashed Peter Wright 18-8 to win his 16th World Matchplay title in his final appearance at the event in Blackpool before retiring.