Federer's third title at the Rotterdam tournament comes a day before he officially returns to the top of the rankings, more than five years after he was last world No. 1.
He will become the oldest person to hold the No. 1 position when the rankings are updated on Monday. It's been more than five years since Federer was last No. 1, and 14 years since he first reached the top spot.
Federer, who has 20 Grand Slams to his name, said his next target is 100 career titles. He moved a step closer Sunday.
Federer said ahead of the final that the more aggressive player would win and Dimitrov started the strongest, winning his first game to love as he slammed powerful forehands and backhands past Federer.
But the Swiss great quickly started matching Dimitrov's groundstrokes and converted his first break point in the fifth game. Federer broke Dimitrov again to go up 5-2 and then served out the set.
Federer kept the pressure on Dimitrov in the second set, breaking the Bulgarian in the first game and continuing to dominate on his way to victory in just 55 minutes.
Federer won a massive 82 percent of points on his service compared to 55 percent for Dimitrov.
After his strong start, the Bulgarian appeared to be struggling physically, but said afterward that he simply wasn't good enough.
Tournament director Richard Krajicek said Dimitrov was ill Saturday night and was short on energy on court.
"Against Roger in the current situation he is in you can't play any less than 100 percent," Dimitrov said.
