Per Sky Sports, the former England international told reporters all he needs is the right players around him:
"I still felt I could do it when I was at Everton, but other people made their decisions on that. Now my ambition is to get Derby back in the Premier League and hopefully play my part there for them.
"Ryan Giggs was able to play into his late thirties in the Premier League and Gareth Barry says he wants to do it at 40. It's important to understand football. It is not all about running round, it is about using your head to play the game.
"Sometimes that gets lost, because you don't score as many goals or whatever. Given the right team around me, then I could still play in the Premier League. The two teams I played for in the Premier League were Manchester United and Everton. I am at Derby now, and hopefully we can get there with them."
Rooney has joined Derby, where his 18-month contract will start in January. He'll have the role of player-coach with the Rams, who have not enjoyed a strong season and sit closer to the relegation zone than the play-off places.
Rooney played in the Premier League between 2002 and 2018, making his debut with Everton before moving to Manchester United in 2017. He's the team's all-time top scorer and won five Premier League titles with the Red Devils as well as the 2007-08 UEFA Champions League.
He returned to Goodison Park in 2017, but couldn't find much success with his former club and moved to MLS less than a year later. With D.C. United, the veteran forward got back on track:
Derby will hope Rooney's scoring form carries over to the Championship. Martyn Waghorn leads the team with six goals scored, and the Rams have the third-worst attacking record in the division, ahead of only Wigan and Middlesbrough.
They're winless in their last five Championship outings and are coming off a 1-0 loss to Millwall.