“I said before the play-off final that my heart was in Sunderland – I wanted to stay, and this made it the most important game of my life. Together, we did it,” Le Fee told the club website.
“From the moment I arrived, I have enjoyed my football, my team-mates, and our supporters. We shared an incredible experience, and now we get to take the next step.
“There are greater challenges ahead, but we must face them together, and I can’t wait to play for Sunderland in the Premier League.”