He was going through a nasty divorce in 2004, unable to walk past a newsstand without seeing tabloids filled with headlines and photos about his personal life. His game was in similar disarray, knocking him well out of the top 50 in the world and the Ryder Cup standings.
Even now -- especially now -- Montgomerie hasn't forgotten.
Beyond winning the match that clinched outright victory at Oakland Hills, the 43-year-old Scot resurrected his career.
He captured the Order of Merit for a record eighth time. He gained ground on Tiger Woods while paired with him in the third round of the British Open at St. Andrews, although he wound up the runner-up by five shots when it was over. And he was on the verge of winning the U.S. Open until chunking a 7-iron on the last hole at Winged Foot to make double bogey.
'I don't think if I was selected ... I wouldn't have won the Order of Merit last year, that's for sure,' Montgomerie said. 'That selection by Bernhard Langer two years ago was vital for my career. I was 41 at the time, and it was not looking good. The last few years were not good, both on and off the course. It wasn't good at all.
'That pick, I believe, saved me in many, many ways.'
He is no longer a troubled soul looking for a handout. He easily qualified for this team, making this his eighth consecutive Ryder Cup.
And there is little doubt who is the juggernaut of this European team heading into the start of the event Friday.
'If I had to pick one player out who has been their most outstanding Ryder Cupper over the last decade, it's been Colin Montgomerie,' Stewart Cink said Tuesday.
The record speaks for itself.
Montgomerie is 19-8-5 in the Ryder Cup, contributing 21 1/2 points to the European cause in his career. He could break the record of 25 career points by Nick Faldo by winning four points at The K Club, and that's not out of the question. He won three points from the four matches he played at Oakland Hills, including the decisive match against David Toms.
And he might end up playing all five matches this week, with just about anyone.
'Colin is there as a leader of the team, and I'm prepared to play him with anybody,' captain Ian Woosnam said. 'If it comes to playing with a rookie, I wouldn't hesitate to do that.'
There is something about this event that brings out the best in Monty.
No one has won more Order of Merit titles in Europe, and yet he is equally known as the best player never to have won a major, not to mention the best player to have never won an official event in America.
He didn't show much mettle at Winged Foot, perhaps his greatest chance ever to win a major. Montgomerie was in the 18th fairway and tied for the lead. But he missed his 7-iron so badly that it came up well short of the green, in grass so deep he couldn't get it close to the hole. He three-putted for double bogey, finishing one shot behind.
It raised questions, for sure, whether he could perform under the stiffest pressure.
And yet, he delivers time and again in the Ryder Cup.
Montgomerie is 1-7 in playoffs on the European tour, and 0-2 in playoffs in the majors. But in his seven Ryder Cups, he has never lost in singles, compiling a 5-0-2 record. Along with beating Toms for the clinching point last time, he hammered Scott Hoch while going first off at The Belfry in 2002, a match that set the tone for Europe's victory.
This is his favorite event, which is easy for him to say since he has never won a major.
But there's deep-rooted truth to that feeling, and it shows in the way he plays, the confidence he carries, and the goals he tries to achieve. Even last time, in such a euphoric moment, he dressed down a British television reporter who tried to suggest it was one of his highest personal moments.
'My personal record goes flying out the window, and I'm here for the team,' Montgomerie said Tuesday. 'And I'm sure that my other 11 teammates will come in here and say exactly the same thing. That's why we've done well, and that's why I think we'll do well again.'
The last time Montgomerie was in the press center at the Ryder Cup, champagne was flowing at Oakland Hills.
Considering how he got onto that team, it appeared to be the perfect ending for Montgomerie in a Ryder Cup career that ranked among the best. He even had put himself forward as a candidate to be captain for 2006.
Asked that day outside Detroit whether he was still interested in being captain, Monty never got a chance to answer.
'He will play,' Langer said. 'He's too young to be captain. He needs to play.'
Langer played a big role in that. Montgomerie has never forgotten him for it.