The Swiss genius spent one hour, 38 minutes in lifting the year-end honours in straight sets.
Federer ends his season with eight titles including three of the four Grand Slams and a prize money haul in excess of eight million dollars.
He leaves with 1.2 million dollars for the week and a silver Mercedes R series car.
"I'm so happy. This is year-end event and only the best can make it," said the winner who joins Ilie Nastase on four year-end titles.
"It's fantastic to win it again. Congratulations to David, who's had a great year.
"This is the end of a long season and I'm looking forward to some holiday," said Federer, set for a series of exhibitions next week against Pete Sampras in three Asian cities.
"I hope to come back stronger next year."
Ferrer, who will move to inside the Top five after his debut appearance at the elite season-wrap up tournament, donated his second double-fault of the match to hand Federer a match point.
The Swiss did not hesitate to wrap up a quick afternoon with a crosscourt winner after one hour, 38 minutes.
"Roger is the best in history," said Ferrer after surviving his first career major. "Thanks to the Spanish guys for supporting me this week.
"This is an unbelievable tournament."
Federer finished with 30 winners, breaking Ferrer six times on nine chances.
The Swiss ends another superb season with a 53rd career trophy; he improved his record over Ferrer to 8-0 with the Spaniard winning just one of 18 sets.
Federer swept up the first set with characteristic efficiency, taking just 26 minutes to break the Spaniard twice on his way to lifting the opener on the first of three opportunities.
The error-prone Ferrer didn't help his own cause with 16 unforced errors in a fragile display.
In the second set, the nervous Spaniard began to slowly find some form, staying level with the Swiss on serve until a fatal error in the seventh game handed Federer the break for 4-3.
That opening was all the number one needed to take even tighter control, seizing further opportunity with a love game, 5-3.
Ferrer continued to struggle, saving three set points as he varied his game to try and avoid the lethal Federer backhand which had paid dividends since the start.
But the Swiss finally broke down the defence as he converted on his fourth set point chance to earn a two-set lead after just over an hour on court.
Ferrer began his last stand, forcing Federer to save break points in the opening game of the third before breaking Ferrer in the fourth and final games of the match.
By Bill Scott, dpa