The Toffees paid around £6million for the Dutch international as they beat the transfer deadline to secure his signature.
Heitinga, currently on international duty, is looking forward to getting his Goodison Park career on track.
"It was difficult [to leave] as it was my first year there," he told Sky Sports News.
"I played every game and we were in the Champions League - but the feeling to play for Everton was big.
"I have come to Everton to play in the Champions League and I will give everything for every game.
"I am proud that I signed for the people's club. When I travelled to Liverpool, the first time I stepped onto the training pitch, I felt one of them.
"It is a club with a very big history."