The Spaniard went into the showdown having won nine of his 13 meetings with Dolgopolov. After edging a tight first set, Ferrer, a former world number three, streaked into a double break lead in the second.
He had two match points when Dolgopolov was serving at 1-5 down but failed to convert them. At 5-2 up he served for the match but was broken. Another match point came his way when Dolgopolov was serving at 3-5 but he squandered the opportunity as Dolgopolov held to trail 4-5.
Serving for the match a second time, Ferrer wasted three more match points before finally gaining victory after 86 minutes when a Dolgopolov forehand went long.
The triumph puts Ferrer level on three titles in Bastad with Bjorn Borg and Mats Wilander. Only Magnus Gustafsson has been more successful at the venue. The win will also propel Ferrer 13 places up the world rankings into the top 30 when the ATP lists are released on Monday.