The Spaniard posted a 6-3, 7-6 (7-3) decision at Costa do Sauipe to become a two-time winner of the clay-court tourney. He also took the title in 2008 with a victory over countryman Carlos Moya.
Almagro improved to 2-1 all-time against Dolgopolov, repeating a victory over the Ukrainian at last year's French Open.
The fourth-seeded Dolgopolov, meanwhile, was playing in just his second career finals. He was coming off an impressive showing at the Australian Open, where he made it to quarterfinals before losing to Andy Murray.