Bent followed up after Neil Sullivan could only parry Shefki Kuqi's 51st minute strike and his eighth of the season proved enough as Town kept a third clean sheet in four games.
In a first half of few chances, Leeds had the better of things and even had the ball in the net inside a minute through David Healy's header, but the flag was already up against his strike partner Brian Deane.
Kelvin Davis parried away a fierce angled shot from on-loan John Oster as Leeds continued to press, while Town's only effort in the first half hour was a woefully wide shot from centre-half Jason De Vos.
Bent had a chance on 34 minutes with a firm header from Kevin Horlock's free-kick, but it was straight at Sullivan, before a curling Horlock effort was easily taken by the Leeds 'keeper.
A dangerous Ian Westlake cross was cleared away as Town made a strong start to the second half, and six minutes into the period they got what proved the only goal.
Clarke Carlisle failed to cut out Horlock's through ball and it spun to Kuqi whose volley was parried into the air by Sullivan, only for Bent to get ahead of Danny Pugh and nudge it over the line.
Leeds may feel Sullivan had the ball back into his hands after Bent's first touch took it towards the keeper, but he appeared never to be in full control, and ref Alan Wiley, who was excellently placed, was happy to let it stand.
Westlake, Bent and sub Dean Bowditch all sent shots over the bar as Town pressed for a second, while Leeds lost their cool and started to commit numerous unnecessary petty fouls.
One earned a yellow card for former Town midfielder Jermaine Wright, who had a miserable afternoon and his substitution on 74 minutes brought one of the biggest cheers of the day from the home fans in a season's best crowd of 29,955.
Healy lifted a shot over from a Pugh cross in a rare Leeds attack, while at the other end, Gary Kelly cleared a dangerous Bent cross, before Bowditch saw a stinging shot deflected over.
An unmarked Kuqi headed a Jim Magilton corner wide, before a long throw caused chaos at the back for Ipswich, before Davis grabbed the ball off Healy's toe.
Leeds almost snatched a point three minutes from time, when sub Julian Joachim's flick from a Pugh corner fell to Deane who swivelled and shot from inside the six-yard box, but Davis plunged to make a superb save.
Town saw out the remaining minutes comfortably enough to extend their unbeaten start to the season at Portman Road and their club record streak of goals in regular season League games to 31.