The 25-year-old British number one overpowered her Danish opponent – a former world number one – 6-4 6-3.
Konta, who in June 2015 was the world number 146, will climb to seventh from 11th in the rankings – her highest yet.
She also takes home £940,000 in prize money in claiming what was her third WTA Tour success from a fourth final.
Konta won her first WTA title in July 2016 at the Bank of the West Classic, was defeated in the China Open final in October 2016 and in January triumphed at the Sydney International without dropping a set.
But this was her first success at a higher level – the top ‘Premier Mandatory’ rung of the WTA Tour.
Having beaten Wozniacki, 26, in their only previous meeting – in straight sets at the third round of this year’s Australian Open – Konta was pre-match favourite.
And she held her nerve with a strong all-round performance to edge her opponent in a tight match.
“Thank you so much to the crowd,” Konta said.
“You guys were incredible through the whole week. Miami is such an energetic city and you guys really bring that to the court.
“My whole team – thank you so much, we’re having a great time working hard and I’m looking forward to continuing to do so.”
Wozniacki reached her career high ranking of world number one in October 2010, and victory in Miami would have been her first at this level since Indian Wells in 2011.
But instead she suffered a third final defeat of 2017 – following losses to Elina Svitolina in the Dubai Championships and to Karolina Pliskova in the Qatar Open.
“Jo, you played really well today,” Wozniacki said.
“You were the better player and deserved to win. I’m hoping third time lucky [against Konta]. We’ll play another time and I’ll try my best to win. I was hoping it would be third final lucky this year, but I’ll have to go for a fourth.”
