Suarez Navarro's first win on the WTA tour since Estoril in April 2014 ended a run of three losses in finals, all last year.
She was building to a win after reaching the semifinals in Brisbane and quarterfinals of the Australian Open. Ostapenko, meanwhile, came to Doha with only two match wins in five tournaments but had won their only previous match last year at Wimbledon.
Ostapenko, the 2014 Junior Wimbledon winner, broke Suarez Navarro twice in the first three games to be 3-0 before wrapping up the set 6-1.
While Ostapenko served five aces to none by her rival and hit 25 winners compared with nine by the champion, it was Suarez Navarro's experience in reducing errors from the second set onward that helped her win.
"My aim at the start of the year was to win one title and to get inside the top 10. I am happy I have done both this week," said Suarez Navarro, who will rise from 11th in the rankings to sixth on Monday.
"I am so emotional right now. I started a little bit nervous and she started really good. You know, losing the first set is never easy. You can only believe in yourself, fight, run, and try to put the ball back in the court.
"The win gives me a lot of confidence going forward in the season. I've lost a lot of finals so I'm really happy and excited about this tournament."
Suarez Navarro returned to court for the doubles final with Sara Errani, but they lost.