Djokovic also won in 2007 and last year. Only six-time champion Andre Agassi won more men's titles.
The lone break point Djokovic faced came in the fifth game, and he erased that. In the tiebreaker he lost only one service point, went ahead to stay when Murray double-faulted to make it 3-2, and closed out the victory when the Scotsman sailed his final forehand long.
Djokovic didn't lose a set in six rounds, and saved 25 of 30 break points against him.
"I had a great tournament," Djokovic said. "I managed to play my best tennis when I needed to."
He improved to 20-2 this year and 90-8 since the start of 2011. He has won five Grand Slam titles, including the past three in a row.
Now begins the clay season culminating with the French Open, the only major event Djokovic has yet to win.
The No. 4-seeded Murray was fresh but rusty after needing only three matches to reach the final. He advanced twice due to walkovers, and was playing for the first time since Wednesday, which may have explained his slow start.
The lopsided early score was a bit misleading, but Djokovic won the pivotal points and hit an ace to close out the 47-minute first set.
The tense second set featured a succession of entertaining rallies. Djokovic lost one 26-stroke baseline exchange that left him panting, hands on his knees on the sunny, hot afternoon.
Eager to finish, he twice was forced to deuce on his serve in the second set and slapped his hips in frustration more than once, wary of a Murray rally.
"That's why he's right at the top — he always comes back, even if you feel you have control of the match," Djokovic said. "I'm really happy to close it out in straight sets."
The final matched two of the game's best returners, but it was serving that dominated. Murray faced eight break points and erased six.
Djokovic's serve was even better. When the Serb had closed out the win, he screamed to match the roar from the crowd, looked to the sky, pumped his arms and blew kisses — a celebratory routine now well-rehearsed.