Anderson (26) was the first South African to reach the final of the Sydney International.
Tomic claimed his eighth straight win of the year in downing the 36th-ranked Anderson 6-3, 6-7 (2/7), 6-3 in one hour and 55 minutes, setting himself up for the Australian Open, which begins Monday, and saying he felt "unstoppable".
Tomic is the first Australian winner of the Sydney tournament since Lleyton Hewitt in 2005 and the first 20-year-old event winner since Roger Federer in 2002.
"I couldn't ask for anything more. It's an amazing feeling," Tomic said.
"Now that I know what it feels like to win a tournament, and it's the best feeling in the world.
"I'm so happy I won. I can't stop here now. Now I've got to look to the next tournament and keep playing the tennis I've been playing."
He will head the Australian Open in Melbourne with his ranking down to 43 and with a chance of facing the 17-time Grand Slam champion and second seed Federer in the third round.
Tomic begins with a match against Argentina's Leonardo Mayer on Tuesday.
Unstoppable
"I've got a good opponent in the first round and I'm playing great tennis. I feel unstoppable. I feel like I'm playing great tennis," he said.
"When you know that no one can beat you, not even the No.1, you've got a good feeling.
"It's amazing stepping on court. You're so confident. That's going to be taken down to Melbourne and I'm going to use that for every match I play there."
Tomic began confidently, breaking Anderson's opening service game and holding a break point in the sixth game before wrapping up the set in 28 minutes.
But he encountered stiffer opposition from Anderson in the second set, fighting off a break point on serve in the eighth game before taking it to a tiebreaker, which the South African dominated to make it one set all.
Tomic had Anderson's serve under pressure in the third set, breaking in the eighth game on his fourth break point when Anderson double-faulted.
Tomic confidently served out for the match for his first career senior title. It was his second victory over Anderson.
The confident youngster has begun 2013 in blazing style starting with three wins in the mixed teams Hopman Cup, including a triumph in Perth over world number one Novak Djokovic.
"I'm really fit and that's why I feel fine," Tomic said.
"It's just amazing what I've done the last few months and got my body to where it is and my tennis is improving each day.
"To get all these matches under my belt is a big confidence and this is what you need in this sport." – AFP.