Scottish underdog Burns had boldly relinquished his WBO super-featherweight title in order to meet Katsidis for the same body's 'interim' lightweight belt.
The Coatbridge fighter knew victory in London would put him in line to become a two-weight world champion and he seized his opportunity, defying bookmakers with a classy performance which earned him a unanimous points win with scores of 117-112 and 117-111 twice.
Burns, 28, came into tonight's bout riding the crest of a wave having won the WBO super-featherweight belt with a magnificent win over Roman Martinez last year.
Since then the Scot had won all three defences - albeit against modest challengers - and was taking a huge step up against a man boasting fearsome stoppage victories against Britons Graham Earl and Kevin Mitchell.
Katsidis, with a 28-4 (23 KO's) record heading into the contest, is regarded as a world-class operator despite his failure to win a title outright and his four losses came against some of the sport's finest.
Burns - 32-2 with nine knockouts before the first bell - was well backed by locals and travelling supporters and began well, operating behind the jab as Katsidis looked to load up power shots.
Two rights early in the second round - one a hook by the ear and the other a straight shot - showed Burns was not fazed by his opponent's reputation, while an uppercut also caught out the Australian.
It was not entirely one-way traffic, with Katsidis staying in close and throwing power shots, but Burns was winning the rounds and an impressive third saw him regularly landing hard left hooks to the body and countering with uppercuts.
Katsidis landed a good straight right through Burns's guard in the fourth round but the Scot responded once more with a right uppercut to give his opponent something to ponder.
Katsidis was cut under the left eye by the end of that session as a difficult night got even tougher, but he improved somewhat in the fifth without really imposing himself.
Burns was boxing beautifully and regularly landing sharp counter-attacks, though he still allowed himself to be backed up to the ropes occasionally by Katsidis's crude onslaughts.
Katsidis was the aggressor throughout but Burns was producing by far the more accurate work, though he was hurt by some questionable head movement on the Australian's part in the eighth.
Katsidis was at least landing a higher percentage of his shots in the middle rounds but another minor cut opened over his left eye in the ninth.
He caught Burns with a winging right and glancing left in the 10th, but the Scot was untroubled.
Indeed, his measured work and snappy shots were winning him the fight against Katsidis's crude flurries and a right hand jarred his opponent's head back.
Katsidis went for broke in the final session, hooking away with savage desperation.
But Burns rode out the storm and after both men laid it all on the line in the last minute, a delighted crowd showed their appreciation at the final bell as the scores confirmed his superiority.
Burns admitted the gamble paid off.
"I treat every fight the same," he said. "It's my job and that's how I see it.
"I'm not scared of getting beaten because a loss is not the end of the world, so I'm willing to fight anyone.
"It's about putting on a show and we did that tonight."