Liv- returned to top spot in the League courtesy of a Paul Watson first half header and a late strike from supersub Iain Russell.
After last week's shock defeat at Forfar, Livi hit the Sons right from the whistle and should have gone ahead after only 5 minutes, but Craig Barr was unlucky to see his shot rebound off the woodwork.
However they were not to be denied, and Paul Watson scored his first of the season on 17 minutes when he rose unmarked to nod home Aaron Conway's in-swinging corner from 8 yards.
Kyle Jacobs, Conway and Raffaele De Vita also came close, with the Italian hitman coming closest but only managing to find the side netting. Dumbarton to their credit stayed with the pace and forced Bullock into a couple of fine stops.
But substitute Iain Russell sealed all 3 points as full time neared, coming straight off the bench to slot a sweet left foot shot low into the net after a mazy run through the Sons' defence.
And with that, Livi returned to pole position in the League.
Livingston: Bullock, C.Barr, MacDonald, Watson, Malone, Ky.Jacobs, Fox, B.Barr, Conway (Sinclair 71), De Vita, Winters (Russell 80)
Subs Not Used: McDowall, Hastings, Cummings
Dumbarton: Grindley, Devlin, Creaney, Gordon, Nugent, Geggan (McStay 83), McNiff, McLeish, McShane, Gilhaney (Brannan 69), Campbell
Subs Not Used: White, Chisholm, Cook