The striker picked up a loose ball inside the Dunfermline half before beating Allan McGregor with a 25-yard shot which found the top corner.
It gave Livi their first win at East End Park for over four years and left the Pars propping up the table.
Yannick Zambernardi underlined Dunfermline's positive start when he lofted the ball over Ludovic Roy from 35 yards and was unfortunate to see his effort come back off the top of the crossbar.
Livingston were similarly unlucky at the other after a terrible mix-up between Scott Wilson and Greg Shields on the halfway line.
Jason Dair sought to take advantage with a superb 25-yard chip which beat McGregor but struck the face of the crossbar.
It was an open game but Dunfermline had their chances to lead at the interval. Roy made a magnificent save to tip an Ian Campbell shot over his crossbar before Campbell thumped a free-kick a yard wide.
Greg Ross had another opportunity when he was put through by Noel Hunt but his shot lacked conviction and Roy saved with his right boot.
But it was Livi who made the breakthrough after 61 minutes. Dalglish, who had threatened a couple of times earlier in the half, picked up the ball in midfield before unleashing an unstoppable shot past McGregor.
Dunfermline threw everything forward to try and salvage the game but failed to force Roy to save another direct shot.
The Pars fans let their feelings known at the final whistle as they booed their team off the pitch.