After failing to agree a new contract at Tottenham Hotspur, Walker switched to City in a £50m deal earlier this summer.
The England international made his debut for the Citizens in Saturday's late kickoff in the Premier League, and the 27-year-old has said that he is now 'enjoying his football again'.
"We needed the win and it was good to get off to a good start, so we are happy. I am enjoying working with the club, the lads have been so welcoming and I am enjoying my football. It is better to play with a smile on your face," Walker told BT Sport.
Walker appeared in 33 of Tottenham's 38 Premier League matches last season.