Davidson told the club's official website: "I'm absolutely delighted.

"This football club has been a massive part of my life and to know that I will be here for a few more years is very pleasing.

"What we achieved last season was absolutely fantastic and we now look to build on that as we all move forward together.

"I have a great backroom staff and a great bunch of lads in the playing squad. They have all been fantastic.

"Everybody in the football department, and all around the club, will continue to give their all as we look to keep moving forward and doing as well as we possibly can."

Chairman Steve Brown said: "Callum is the most successful manager in our history and one of the finest young managers in British football.

"We are all delighted he has signed this new contract. It really is great news.

"When I appointed him last summer I told him he'd be given time to develop as a manager and he excelled in that environment.

"This long-term deal will allow him to develop further, knowing that he has the full backing of everyone at the football club.

"We have great unity at St Johnstone and we are together as we try our best to give what our supporters deserve.

"I said last week that we'd reinvest in the football department. Today is the start of that process.

"We will continue our hard work behind the scenes to enable us to continue to move forward."