The South Africa international moved to White Hart Lane in January 2011, but failed to hold down a regular starting position with the north London side.
After spending the second half of last season at Goodison Park the Toffees were keen to bring the playmaker back to Merseyside on a permanent basis, and Pienaar is glad that a £4.5 million move has been wrapped up.
“I am happy to be here. It took a few weeks to sort out but I am delighted to be back and excited to play for Everton,” he told the club’s official website.
“There was no doubt in my mind that I would be back here. At the end of the season, I told the manager how I felt and I am happy now it is all done.”
Pienaar joins Steven Naismith as Everton’s new players acquired this summer.
By Gareth McKnight