Celtic's Chief Executive Peter Lawwell praised Lennon and called him a winner.
"This is a fantastic day, a fantastic achievement, and it will probably never to be repeated. Neil, in our moment of need, stood up to the plate. He's done a fantastic job in difficult circumstances, and when you look at his credentials - he's a Celtic man, he's made for Celtic, he knows what's required and he's a winner," club's official website quoted.
Lennon had replaced Brendan Rodgers as Celtic manager and guided the club to a third consecutive domestic treble after they won the Scottish Cup and Lawwell said that Lennon has earned the right to be the permanent manager.
"There's no better candidate, and Neil has earned the right to be the permanent manager of Celtic, based on our recent performances and also who he is as a manager. Winning the Treble Treble is historic and Brendan clearly takes a lot of credit for it. We probably wouldn't be here today if it wasn't for him, in terms of the magnificent period as manager, and we will be forever grateful to him," he said.