Ireland joined Villa as part of the deal that saw Milner move to big-spending City, with the 23-year-old believing he was not given a fair chance under manager Roberto Mancini.
"I did feel unwanted at Manchester City," he said. "I was banging my head against a brick wall despite what I had done in training.
"I just went with the reserves, worked hard in the gym and kept as active as possible. Without a shadow of doubt the situation I found myself in will happen a lot at Manchester City with all the high-profile players they have at the club.
"At Manchester City sitting on the bench I didn't feel part of the team. I was neither happy or sad if we lost. I'm still young and hopefully Villa will get the best of me and I am now looking forward to the season.''
The Republic of Ireland player, who is set to make his Villa debut against Newcastle on Sunday, his 24th birthday, has also warned Milner he may have to get used to not being a certain starter with City.
Mancini has a host of world-class players to call on and Ireland said of Milner: "I can see why he wanted to go to Manchester City. He can see the attraction of the move and the opportunity to become more established and become a superstar.
"But he faces a challenge of holding down a regular first-team place. I may have been forced out but I couldn't be more happy to be at Aston Villa.
"Richard Dunne is a good example of what can happen after leaving Manchester City to join Villa.
"A year on I can see how happy he is at Villa and I'm hoping that I will be as happy in a year's time. Richard was a huge part of Manchester City and it was a great shock to see him leave.
"It was as big a shock to him as everyone else but he could not have come to a better club as he proved with his performances last season. For me this is a positive, as this is exactly I want it to be.''
Villa's caretaker manager Kevin MacDonald is delighted to have Ireland on board.
MacDonald knows the attributes of Ireland as well as anyone, having coached him when he was the assistant to the then Republic of Ireland manager Steve Staunton.
MacDonald, who is still refusing to be drawn on whether he wants to succeed Martin O'Neill on a permanent basis in the Villa Park hot-seat, said: "Stephen Ireland is a very talented player. He is different from James Milner who is a power player.
"James has the drive to break the game up. He probably doesn't get into the box as much as Stephen Ireland. I think he glides across the pitch.
"I remember the first time I saw him training with the Republic of Ireland. I just thought I hadn't seen the kid before. He glides past people and rides tackles easily.
"His awareness of where his team-mates are on the pitch is fantastic and his choice on the weight of pass is one of his real plusses.'' As for his own future, MacDonald added: "It's been nice so far but I am a reasonably intelligent man that I would know whether to accept or decline the job.
"I have no problem with the timescale as Mr Lerner (Villa's owner Randy Lerner) will be looking seriously at what he wants to do.''