Two quickfire goals at the start of the second half from captain Johnnie Jackson and Ricardo Fuller did the damage as the Addicks picked up their first win in five and their first away from home this season.
Jason Scotland reduced the arrears when his long-range effort deflected off the unfortunate Michael Morrison, but the hosts could not fashion a leveller in the remaining half-hour and were greeted with a chorus of boos by the Portman Road faithful at the final whistle.
It was a clash between two sides whose struggles in the Championship were very much mirrored going into the encounter, however the greater pressure was certainly on second-bottom Town, who also had one win to their name but found themselves in their lowest league position for three seasons.
And that makes this latest setback all the more painful for the Suffolk club, now winless in five and still to triumph at home, and puts Jewell in a precarious position.
Jewell's threadbare squad was stretched even further by the damaging loss of strike partners Paul Taylor and Michael Chopra to injury, with new loan signing Danny Higginbotham on the bench.
Charlton boss Chris Powell, meanwhile, also lost the services of Yann Kermorgant and duly handed a first start to former Stoke frontman Fuller.
Despite the absence of Taylor and Chopra, Town looked lively in attack early on with Daryl Murphy and Jason Scotland both enjoying opportunities.
Salim Kerkar, recalled by Powell, came within inches of connecting from close range at the other end as both sides enjoyed half chances.
Charlton restored the balance of play following Town's early dominance, Dale Stephens' speculative long-range effort forcing a solid parried save from Scott Loach.
Yet clear-cut chances were severely lacking and the excitement of the opening quarter had long disappeared by the time referee Martin Atkinson brought the first half to a close.
Jewell turned to Nathan Ellington at the break, handing the marksman his first appearance since January.
But the second half started in disastrous fashion for the hosts.
A teasing ball from the right evaded Bradley Wright-Phillips but was recycled on the left and sent back in to the Ipswich area to be finished by Jackson.
Matters soon went from bad to worse as Massimo Luongo lost the ball, sparking a Charlton counter which resulted in Fuller drilling the ball home from the right side of the penalty area.
However, Scotland reduced the arrears in fortuitous fashion in the 57th minute when his tame effort from distance took a huge deflection off Morrison to wrong foot Ben Hamer.
Yet despite plenty of endeavour, mixed with little quality, the home side were unable to force a leveller, with Ellington blazing over late on, much to the disapproval of the vocal home support.