Ruud managed five ATP titles in 2021 and followed that up with another one in the new season as he recovered from a first-set scare to overcome local favourite Schwartzman 5-7 6-2 6-3 in Buenos Aires.
The Norwegian extended his record at the tournament to 9-0, having already lifted the trophy in 2020, after negotiating past his Argentinian opponent in two hours and 35 minutes.
Ruud, who was the top seed, had not dropped a set all week on his way to the showpiece final, but he faltered in the first set as he spurned a break point at 5-4 up, with Schwartzman holding to make it 5-5 before subsequently claiming the opener.
Schwartzman repeated the feat in his first service game of the following set, staving off four break points, but Ruud rallied at 2-2 to claim four straight games and send the match to a decider.
Schwartzman was the defending champion after ending a 13-year wait for an Argentinian winner in Buenos Aires, though it was Ruud who lifted the trophy as he overcame an early break to extend his winning streak in ATP 250 events on clay to 18.