Finch surpassed the previous record of 123 set by New Zealand's Brendon McCullum against Bangladesh at Pallekele in September last year.
Remarkably, Finch got off the mark, reached his 50, hundred and 150, with sixes.
The 26-year-old Victorian faced just 63 balls, including 11 fours and 14 sixes -- 128 of his runs coming in boundaries -- in an innings that ended when he was bowled by Jade Dernbach.
His 14 sixes were also a world record for the most in any T20 international individual innings.
Finch's century was only the 10th in all T20 internationals, the first by an Australian and the first by any batsman in England.
Highest Twenty20 international innings (score, balls, fours, sixes, player, country, opponent, venue, year):
156 63 11 14 Aaron Finch AUS v ENG Southampton 2013
123 58 11 7 Brendon McCullum NZL v BAN Pallekele 2012
117 no 51 5 13 Richard Levi RSA v NZL Hamilton 2012
117 57 7 10 Chris Gayle WIS v RSA Johannesburg 2007
116 no 56 12 8 Brendon McCullum NZL v AUS Christchurch 2010
104 no 57 12 5 Tillakaratne Dilshan SRI v AUS Pallekele 2011
101 no 69 9 6 Martin Guptill NZL v RSA East London 2012
101 60 9 5 Suresh Raina IND v RSA Gros Islet 2010
100 64 10 4 Mahela Jayawardene SRI v ZIM Providence 2010
100 58 10 5 Richard Berrington SCO v BAN The Hague 2012
Australia's Aaron Finch sets new T20 high score with 156 off 63 balls
Advertisement