The 29-year-old striker, who completed his move to Rugby Park on Thursday, has played for clubs in England, Turkey and the United States.
"I said at the end of last season that I had enjoyed being back at Kilmarnock," Sky Sports News quotes Boyd as saying.
"It was always my first thought to try and get something sorted here because my family is back here and settled. We had to sort a few things out but it was a pretty easy decision in the end.
"I spoke to a few other teams during the summer, with the most tempting offer from Davie Weir at Sheffield United. We are close mates and Sheffield United is a big club.
"It was a move that crossed my mind but with my family being settled here and the travelling that would have been involved, I felt it was more important for me to concentrate on playing my football here in Scotland.
Boyd scored three goals in nine matches for Kilmarnock last season.