Brazilian midfielder Gilberto Silva scored a late goal to salvage a point for Arsenal in their first Premiership match at the Emirates Stadium.
Silva capitalised on good work by Walcott to score
Villa skipper Olof Mellberg gave the visitors a shock lead when he headed in from a corner after 53 minutes.
Gilberto equalised six minutes before the end following excellent work from teenage substitute Theo Walcott.
Villa then withstood a late onslaught to ensure that Martin O'Neill's tenure as manager got off to a great start.
O'Neill, who was appointed Villa boss at the start of August, seems to have immediately suffused confidence and belief into his young side.
Gareth Barry, Steven Davis and Gavin McCann were outstanding for the visitors in midfield while 19-year-old Gabriel Agbonlahor was a real threat on the break.
Arsenal were their usual blend of touch and movement, dominating possession and creating a host of chances, but they lacked sharpness in front of goal.
Agbonlahor had the first good chance of the game when he drew a smart save from Jens Lehmann with a volley from 15 yards.
Thierry Henry was predictably the main threat for the hosts and had a hat-trick of shots from the edge of the area, all of which flew over the crossbar.
The Gunners thought they had broken the deadlock after three minutes of first-half stoppage time.
Kole Toure headed in a free-kick from close range, but his effort was ruled out for offside.
O'Neill admitted he had not expected such a good start
The goal would have been hard on Villa, who were organised and resilient, in sharp contrast to their showings under David O'Leary at the end of last season.
The home crowd were incensed shortly after the interval when Emmanuel Eboue went down following a tussle with Luke Moore.
As new Premier League guidelines dictate, Villa played on when referee Graham Poll did not whistle.
If the Arsenal supporters were angry with that decision, they were stunned when the visitors scored the first goal in a competitive game at the Emirates Stadium.
Lehmann failed to collect a left-wing corner, Mellberg rising above Emmanuel Adebayor to head into an unguarded net.
Arsenal responded by laying siege to the Villa goal but struggled to find a way through.
Adebayor almost atoned for his earlier error but saw his close-range effort cleared off the line by Liam Ridgewell.
Walcott was brought on for his first Premiership appearance and played a key role in Arsenal's equaliser.
His cross from the left eventually fell to Gilberto, who thumped a volley into the roof of the net.
Arsenal boss Arsene Wenger on Theo Walcott:
"I know a lot is expected from him but I am pleased.
"He had that sharpness that we missed and was dangerous on the left flank. He was involved in the goal and his overall performance was very positive.
"It was a typical beginning of the season game where the players were not completely ready physically, added to the fact that many of them played 90 minutes in midweek."
Aston Villa boss Martin O'Neill:
"I'm still trying to get to know my players, but I thought they were terrific it's a great result.
"It is a big boost to confidence. If we had been hammered it would have looked like a long hard season.
"I cannot do anything about the expectation but we are not going to become a really decent team overnight."
Arsenal: Lehmann, Eboue, Toure, Djourou, Hoyte (Flamini 80), Hleb, Fabregas, Silva, Ljungberg (Walcott 73), Adebayor (Van Persie 65), Henry.
Subs Not Used: Almunia, Cygan.
Goals: Silva 84.
Aston Villa: Sorensen, Hughes, Mellberg, Ridgewell, Samuel, Agbonlahor, McCann, Davis (Hendrie 83), Barry, Angel (Laursen 90), Moore (Djemba-Djemba 89).
Subs Not Used: Taylor, Phillips.
Booked: Hendrie, Angel.
Goals: Mellberg 53.
Ref: G Poll (Hertfordshire).