Lions hitman Marc McNulty netted his second and third goal in two games to help Livingston seal their first league win of the season.
Livi dominated the first half and were very unlucky to go into the break behind.
Dumbarton took the lead a minute before the break through Mitch Megginson’s strike from the edge of the area.
But Livi stuck to their task and took charge of the game after the interval.
They deservedly levelled when McNulty prodded home Mike Mampuya’s deft cross for his first of the day to level the match.
And Andy Barrowman teed up McNulty for his second, with 15 minutes to go, and the Lions left The Rock with three vital points.
Dumbarton: Ewings, McGinn, Barry, Graham, Linton (K.Smith 81), Gilhaney, Murray (Prunty 80), Turner, Agnew (Fleming 77), Megginson, Nish
Subs not used: Grindlay, S.Smith, Kirkpatrick, McKerrechar
Livingston: Jamieson, Mampuya, Donaldson, Mensing, Fordyce (Jacobs 46), McDonald, O'Brien, Scott, Scougall (Burchill 77), McNulty (Denholm 90), Barrowman
Subs not used: Walker, Wilkie, Mullen, Lander
Referee: John Beaton