Rooney is now determined to deliver his best for his boyhood side, while also proving some doubters wrong.
"There is a lot of expectation, coming back here," he said. "There are some fans who maybe thought I wasn't good enough to come back here, but it is up to me to prove myself.
"I have been working hard and I am ready for that challenge to prove myself. I could have gone to another Premier League team and taken my foot off the gas and seen the last few years out. But coming back here? I have got to be the best I can be.
"It is the club I grew up supporting, it's the club I want to play for. I want to do well. I knew when I came back, I was putting a lot of pressure on myself. That is how I like to play."
Everton (@Everton) August 13, 2017
When Rooney burst onto the scene with the Toffees in 2002, he was a bustling teenager with a potent combination of pace, power and aggression.
Over the course of his United career, during which he became the club's and his country's all-time record goalscorer, his game has evolved and the 31-year-old is confident he still has much to offer.
"Football fans aren't silly," he said. "Everyone knows I'm not the explosive player who was here when I was 16 to 18. I think I'm a lot cleverer than I was back then.
"My game has changed. Hopefully the change in my game can help the team."