The West Brom forward came from the bench to score the only goal and give Giovanni Trapattoni a headache over who will partner Robbie Keane in Poland and Ukraine.
In a game lacking any real spark and quality, minus that on offer from halftime substitute Aiden McGeady, Long's header in the 77th minute, ensured another win for Giovanni Trapattoni's side ahead of this summer's European Championships.
Ireland began with Sunderland starlet James McClean making his full debut for the side and Kieran Westwood deputizing for Shay Given in goal, while Paul McShane also started, at right back in the absence of John O'Shea, despite not being a part of Giovanni Trapattoni's squad for Euro 2012.
Bosnia failed to qualify for the championships in Poland and Ukraine this summer, having been beaten in the playoffs by Portugal, but the team settled the quicker of the two sides at Lansdowne Road and created the first meaningful opportunity of the match in only the third minute.
Clever play down the right between Edin Dzeko and the Roma midfielder Miralem Pjanic, freed the Manchester City striker who crossed for Vedad Ibisevic, and the Stuttgart striker was mere inches away from turning the ball past Westwood.
Minutes later and the two sides exchanged rather hopeful penalty appeals. First, Ireland's Glenn Whelan burst through on goal and appeared to be brought down by his Stoke teammate Asmir Begovic, before Zvjezdan Misimovic, the Dinamo Moscow playmaker and Bosnia captain, saw his shaped effort blocked by the body of McShane. However, on both occasions the referee remained unmoved.
Ireland was gradually growing into the game, and a good spell of patient possession led to a chance for Damien Duff in the 32nd minute, who, cutting in from the right touchline, drilled a daisy cutter of a shot just wide of Begovic's post.
In the 39th minute, Westwood made a comfortable save from a 30-yard strike from Pjanic before 60 seconds later McClean forced a decent save from Begovic at his right post with a low, angled drive.
Ireland took the lead in the 77th, courtesy of Long, the West Brom striker, who showed Walters how to score with a header from six yards, beating Begovic at the back-post after another wonderful pin-point cross from McGeady.
Walters came close to doubling Ireland's lead a minute later, but, having been played clean through, he could only hit his shot against the on-rushing Begovic.
Ireland finished the match much the stronger, with McGeady was at the heart of everything, and the former Celtic man almost teed up Long for a second in injury time.
Picking the ball up in an inside left position, McGeady played a one-two with Walters, before chipping the ball across the box for Long, whose goalbound header was brilliantly saved by Begovic. On the followup, Keith Andrews headed the rebound over the crossbar.
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