McCall has signed a two-year deal which will begin when his initial contract expires at the end of this campaign.
The 48-year-old had begun negotiations well before Christmas and his sustained success at Fir Park has seen him linked with a number of job vacancies.
But he always stressed job satisfaction was his key motivating factor, turning down opportunities to leave in the past, and only his relaxed approach to the contract situation delayed the deal until Thursday night.
McCall told MFCTV: "As I have said on numerous occasions, there was never any issues, it was just a case of getting round to it. I've been doing my job exactly the same in terms of the squad and you have already seen that with some of the younger players who have signed up.
"There has never been any doubt in my mind but I am pleased it is finally signed. We can now focus all the attention on the last seven matches of this SPL season."
McCall joined Motherwell in the final days of 2010 and has attained consistent results ever since.
The former Scotland midfielder led the club to the top six of the Scottish Premier League and the Scottish Cup final in his first season.
His first full season saw Motherwell finish third in the league and secure a place in the Champions League qualifiers and they now sit second in the table with another season in Europe the target.
Fir Park chief executive Leeann Dempster added: "We are really delighted to have Stuart at the club for a further two years. We have enjoyed real success under his stewardship with a strong backroom staff and playing squad and we hope that we can build on that for the season ahead."