The 27-year-old, who played a prominent part in the R's promotion to the Premier League last season, linked up with fellow new boys Leicester City.
Despite being surprised by the nature of the move, Simpson says that he is happy with his start to life at the King Power Stadium.
"Football is football and you never know what will happen, but it was a shock when QPR told me I was leaving," he told Sky Sports News. "I pretty much played every game last year and I was expecting to start this season, but it has worked out better for me because it is a club going in the right direction from top to bottom.
"They are a great set of lads here and I wanted to be in a team that is progressing and wants to do well in the Premier League. I think we have shown that already. It has been a good start. To beat Manchester United at any time is great but to do it in the way we did, it was tremendous.
"The home form is the key and we are making home a bit of a fortress, especially with the fans. The atmosphere at the KP has been class. It has been electric and I want to be involved on the pitch and feel that."
Simpson has made three appearances for Leicester in all competitions so far this campaign.