Mr Lawwell, who served as Celtic‘s chief executive for 18 years, was forced to quit amid what the club claim is ongoing intimidation after his address was posted online at the weekend.
Under pressure from his family to step down, his departure followed the club’s recent defeat against St Mirren in the Premier Sports Cup final, after which three members of staff were allegedly assaulted.
SPFL CEO Neil Doncaster expressed deep concern over Mr Lawwell’s resignation.
He said: “Peter’s departure is a damning indictment on the behaviour of a very small number of supporters that someone who has been so pivotal to Scottish football for almost a quarter of a century has felt compelled to step down for the sake of his family’s safety.”
Mr Lawwell has been a cornerstone in the growth of the SPFL, having contributed significantly to its success over the years.
Mr Doncaster said it was “enormously disappointing” that he had to leave the club he cares for so dearly.
He added: “This very sad episode merely highlights the need to take a very robust line on the part of the football authorities and others in dealing with the small minority of people who behave in an unacceptable manner in relation to Scotland’s national sport.”
Mr Lawwell’s decision to step down has prompted a stern call to action to curb unacceptable fan behaviour.
Current chief executive Michael Nicholson also expressed his disappointment at Mr Lawwell’s departure.
He said: “It’s a sad day for Celtic because one of our colleagues has felt the need to stand down from his role.
“Peter is a Celtic fan first and foremost and has been a great colleague, a great leader for Celtic, both as chief executive and more recently as chairman, as we have enjoyed great success on and off the pitch.
“I know it was a decision which weighed heavily on him, it is not an easy decision, but he has made the decision for himself and his family because of the abuse and the threats directed towards him.
“Those were behaviours from a very small minority of the Celtic support.
“But those behaviours were completely unacceptable.”
