Villa will pay an initial 18 million pounds (28.7 million dollars) for Bent but additional add-ons mean the final figure could rise by another six million pounds (9.5 million dollars).
Bent's capture surpasses Villa's previous transfer record of 12 million pounds (19.1 million dollars) which they paid twice in separate deals for James Milner and Stewart Downing.
Bent, who handed in a transfer request earlier this week, has agreed a four-and-a-half-year contract and should make his debut in Saturday's Premier League clash against Manchester City at Villa Park.
"Aston Villa is a massive football club and as soon as I knew they were interested in signing me I wanted to join," Bent said.
"The size of the football club and the history of the club are major reasons for me coming here.
"There are some top, top players here too, real quality, and I've been able to speak to the manager and the owner about their ambitions for the club.
"I'm very excited about being a part of what we hope to achieve."
The 26-year-old former Ipswich and Charlton forward moved from Tottenham to Sunderland 18 months ago and scored 25 goals in his first season for the Black Cats.
He has scored 81 Premier League goals in the last five seasons - a figure only bettered by Didier Drogba and Wayne Rooney on 82 apiece. In total he has scored 128 league goals in 308 appearances.
Bent has won seven senior England caps and scored his first goal for his country during the Euro qualifier with Switzerland in Basle in September.
His arrival takes Villa's spending in this transfer window close to the 30 million pounds (47.9 million dollar) mark after the capture of Lyon midfielder Jean Makoun.
While Villa boss Gerard Houllier celebrates a much-needed signing as he tries to lift his struggling team away from the relegation zone, Sunderland boss Steve Bruce was not happy to be losing his star forward.
"It's hugely disappointing that Darren has decided that his future lies away from Sunderland and the players, our supporters and the club as a whole have every right to feel massively let down," Bruce said.
"The timing is especially hard to take, given that we are progressing positively and are in a great position to push on.
"Everyone has been nothing but supportive of Darren in his time at Sunderland but it's obvious he's not been himself in training and we've certainly not seen the best of him in games in recent weeks - and we now understand why."