Dunfermline continued their climb to mid-table respectability under caretaker-boss Jim McIntyre thanks to a Stephen Glass penalty against Morton.
Glass fired home after 15 minutes when Kevin Finlayson fouled Mark Burchill.
Burchill went close minutes afterwards, but a Peter Weatherson shot at the other end struck the underside of the bar before bouncing to safety.
Kieran McAnespie also struck the woodwork shortly after the break, but Dunfermline held on for victory.
Morton: McGurn, Shields, Harding, Greacen, MacGregor, Finlayson, McAnespie (Graham 67), McLaughlin (Templeman 76), McAlistair, Weatherson, Russell (Gardyne ).
Subs Not Used: McKellar, Robinson.
Dunfermline: Gallacher, Woods, Harris, Scott Thomson, Murphy, Simmons, Ryan, Glass, McGlinchey (Crawford 74), Burchill, Hamilton.
Subs Not Used: Phinn, McIntyre, McManus, Murdoch.
Booked: Glass, Harris, Burchill.
Goals: Glass 15 pen.
Ref: C Richmond