The Chinese player - who rises from 20 to 12 in the world after this sucess - produced an assured performance at Event City to win the Steve Davis trophy, the six-times world champion presented him with his prize, and a cheque for £70,000.
The biggest moment of Liang's career comes less than a year after he lost the final of the UK Championship to Neil Robertson.
Liang Wenbo enjoys outrageous luck with back-to-back flukes
Resuming 5-3 ahead from the afternoon session, the action continued to be fast and furious with plenty of heavy break-building pouring out of both men..
A run of 132 from Trump saw him close to 5-4 behind, but he could never quite get level with the inspired Wenbo who has a reputation for losing his cool, but showed composure and character in spades to deny his opponent back-to-back titles after Trump won the European Masters a week ago in Bucharest.
Runs of 84 and 98 carried Wenbo 7-4 to the good before a swift 51 from Bristol's world number three Trump meant it was as you were with Liang remaining two clear at the mid-session interval with a 7-5 lead.
Liang jumps for joy after winning English Open title
A 50 from Trump gave him another chance of levellling, but Liang refused to buckle as a 62 in the 14th frame left him on the cusp of victory before he pounced on a Trump missed red late in the 15th frame to finally scramble over the winning line.
He celebrated wildly and will be boosted before the International Championship begins in Daqing a week today.
English Open champion Liang Wenbo chats to Ronnie O'Sullivan and Jimmy White
FIRST SESSION REPORT
Liang Wenbo holds a 5-3 lead over Judd Trump after a compelling first session of their best-of-17 frame English Open final in Manchester.
China's Wenbo - the world number 20 - opened with a break of 95 to claim the first frame after Trump had missed a black.
That quickly became 2-0 courtesy of another 95 from last year's UK Championship finalist Liang, but Trump, chasing back-to-back titles after his success at the European Masters last Sunday, quickly restored parity by winning the next two frames before the mid-session interval boosted by a 54 in the fourth frame.
Liang Wenbo picks out stunning long red
Wenbo moved ahead by the odd frame in five courtesy of a 76 before a 92 sent him two clear again at 4-2.
A 51 in the seventh frame was not enough for world number three Trump to reduce the deficit as a double on the respotted black enabled Liang to move three frames clear for the first time.
Liang Wenbo produces stunning shot in English Open final
He was in among the balls in the final frame of the afternoon, but he walloped the reds apart after missing a routine red before Trump pieced together a classy 52 to trail by two frames before this evening's closing session.
The first man to nine frames wins the English Open title and a first prize of £70,000.
There is also the distant prospect of a £1m bonus if the champion can add the Northern Ireland Open, Scottish Open and Welsh Open to their name over the next five months as part of the Home Nations Series on Eurosport and Quest.