MAUI, Hawaii, Jan 8, 2013 (AFP) - The big-hitting 28-year-old won the 54-hole event by four strokes, finishing at 16-under 203 for his seventh PGA Tour title.
"It gives me a lot of confidence going into this year," Johnson said. "I played really good golf the last two days.
"I stayed aggressive and hit a couple of bad drives but other than that I played really good golf today."
The tournament was originally supposed to conclude Monday but it didn't officially begin until Monday because of heavy winds at the Kapalua Plantation Course.
Extreme conditions forced organisers to shorten the tournament to 54 holes, with 36 holes taking place on a marathon Monday.
Johnson headed into the final round with a three-shot lead over defending champion Steve Stricker. He maintained his lead during the first Tuesday finish on the Tour in six years.
Stricker had to battle through a nerve problem in his upper thigh. He shot a 69 and finished alone in second place at 12-under.
"He came back strong, I knew it was going to be tough today but I gave him a bit of a run for a while," Stricker said.
Brandt Snedeker (69) placed third at 10-under. Bubba Watson (71) and Keegan Bradley (70) tied for fourth at minus-nine.
Final-round scores on Tuesday in the weather-delayed PGA Tour Tournament of Champions (USA unless noted, tournament shortened to 54 holes, par-73):
203 - Dustin Johnson 69-66-68
207 - Steve Stricker 71-67-69
209 - Brandt Snedeker 70-70-69
210 - Bubba Watson 70-69-71, Keegan Bradley 71-69-70
211 - Rickie Fowler 70-74-67, Tommy Gainey 72-69-70
212 - Carl Pettersson (SWE) 70-72-70
214 - Ian Poulter (ENG) 71-74-69, Matt Kuchar 74-71-69
215 - Mark Wilson 69-76-70, Webb Simpson 72-72-71
216 - J.J. Henry 71-74-71, Johnson Wagner 72-72-72, Scott Stallings 72-74-70, Scott Piercy 72-71-73, Nick Watney 69-73-74
218 - Jonas Blixt (SWE) 72-74-72, Ben Curtis 70-76-72, John Huh 73-71-74, Zach Johnson 74-72-72, Jason Dufner 72-77-69
221 - Charlie Beljan 71-75-75, Bill Haas 71-75-75, Marc Leishman (AUS) 75-75-71
223 - Hunter Mahan 72-77-74, Ted Potter 75-75-73
225 - Ryan Moore 72-77-76, George McNeill 79-73-73
230 - Kyle Stanley 78-80-72