Hercog, who bested Sweden's Johanna Larsson in last year's title tilt to collect her first career WTA crown, this time rallied to get past France's Johansson 0-6, 6-4, 7-5, collecting her second title.
Hercog came into the Sweden event with just one win in her previous eight matches stretching back to April's Charleston tournament.
Johansson had prevented a rematch of last year's finale when she downed Larsson in Saturday's semifinals.
She fell to 0-2 in career finals with the setback.
Exploding whale video goes viral on Internet
Campus cop fatally shoots Texas student during traffic stop