Walker spent the second half of the 2010-11 season on loan at Villa Park, and earned rave reviews for his marauding runs on the right-hand side during sixth months in the Midlands.
The England international told The Sun that joining Villa was the most important move of his career to date.
He said: "It's not one of the best moves I've made, it is the best move.
"I knew I had to go and prove to Tottenham and myself that I could play week-in week-out in the Premier League.
"I went up there and their manager Gerard Houllier promised me he was going to play me in every game.
"To be given my first step in the top flight by Villa was something else and I have alot to thank Villa for."
Walker comes up against his old club this weekend as Paul Lambert's side make the trip to White Hart Lane on Sunday afternoon.