Bennett completed his transfer to Villa Park after the two clubs agreed an undisclosed fee, believed to be around the £2.5million mark.
Bennett, a former Boro youth team player, said: "I am really excited to have joined a massive club in Aston Villa and I'm eager to fight for a starting place and get in the team.
"It's up to the manager to pick the team, of course, but it would be great to go back to the north-east this weekend and make my debut against Newcastle.
"My approach has always been to get forward and try to create things. If I keep working on my game and improving it I know I can succeed at this level and help the team."