The on-loan Sunderland forward tapped in a rebound to give Roy Keane's side a third straight home win and leave Barnsley marooned in mid-table.
Ipswich now look safe from the drop this season and Keane will be content with his side's reaction to their midweek dressing down.
Keane was livid with his side's insipid performance at Watford and admitted he would have replaced most of his team at half-time if he could.
The former Manchester United captain kept his players locked in the dressing room for over an hour at Vicarage Road and the hairdryer treatment had the desired effect as Town made a superb start to the match.
Carlos Edwards - one of the four changes made by Keane - had already rattled a shot over from 25 yards when Murphy gave the hosts a fourth-minute lead.
Another player recalled to the starting line-up made the difference as Pablo Counago darted in from the left flank before chipping over onrushing goalkeeper Luke Steele.
The Spaniard was denied a fine solo goal as the ball struck the far post, but Murphy was on hand to slam in his sixth goal in 11 games for Ipswich from close range.
Defender Gareth McAuley came close to doubling the lead moments later but Steele made a fine reflex save to turn his header away from point-blank range.
The Tykes looked short of ideas and were struggling to come to terms with the sharpness of Town's passing, with Edwards again going close with a long-range drive.
The visitors improved after the break, and midfielder Nathan Doyle had an early effort but dragged his shot wide from the edge of the area.
Emil Hallfredsson then crossed for Filipe Teixeira to lash a shot over the top as Barnsley continued to press before Keane reacted by making a double change.
One substitute Jaime Peters almost made an instant impression but looped a header wide before David Norris hammered a shot on goal but straight at Steele.
Barnsley replacement Reuben Noble-Lazarus then forced Ipswich goalkeeper Brian Murphy into a decent stop with a deflected strike from 12 yards but the home side held on for three more points which lifted them eight points above the drop zone.