The 23-year-old moved to the East Midlands from League One newcomers Exeter on Friday for an undisclosed fee, signing a three-year contract.
He crossed swords with Nigel Clough in the Conference when the Rams boss was manager of Burton and admits he has been hugely impressed by the former England international's ambition.
Moxey told the club's official website: "Derby have offered me a tremendous opportunity and I'll give everything I've got to make a success of it here.
"The gaffer impressed me with his plans for the club and how he intends the team to play their football.
"It's a massive club that has huge potential and I'm looking forward to being part of a squad that will try to fulfil it. I can't wait to get stuck into pre-season training."