He had been confirmed as the Demons' new AFL coach for only a couple of minutes before he was already talking about his exit.
The succession planning that worked so well for Roos and Sydney was a key reason that he decided to return to AFL coaching and take over the ailing Demons.
One of the first key steps for the Demons will be to appoint a senior assistant who will take over from Roos in two or three years.
"This has to work for Melbourne," Roos said at Friday's announcement.
"They have to be wedded to a succession plan and it's something we'll start, I guess, early next week.
"I'm extremely, extremely excited to be introduced as the Melbourne coach."
The Swans' succession plan involved Roos handing over the senior coaching role to assistant John Longmire, who masterminded last year's premiership.
Roos' appointment caps a three-month campaign by Melbourne chief executive Peter Jackson to lure the 2005 Sydney premiership coach back into AFL senior coaching.
As soon as Melbourne sacked Mark Neeld earlier this season, it was clear they would go after Roos.
But the man himself was equally adamant it would not happen.
It was only when Roos ended his job as head of Sydney's junior talent academy, finally cutting all formal ties with the Swans, that he started considering the Melbourne job.
Then Jackson put the succession idea to him.
"Peter is a very dogged character and I'd probably play him in the back pocket," Roos said.
"So he kept on asking and asking and we kept on speaking and speaking.
"That (succession) really, really sparked the interest in terms of where I was going in my career and what I was looking to do."
For Melbourne, the importance of securing Roos cannot be understated.
Jackson said it was the biggest moment in their history since Ron Barassi stunned football by leaving the Demons and going to Carlton in 1965.
Melbourne have not won a premiership since 1964.
They were second last this season with only two wins and an appalling percentage of 54.
This is the first time Melbourne have secured an AFL premiership coach to take over the team since Barassi returned in 1981 for five unsuccessful seasons.
"I know exactly what I'm coming into ... I know it's going to be a very difficult job," Roos said.
"I know in the research that I've done, that I have a group that will work hard.
"That, as a coach, gives me great confidence."
Jackson said Roos' impact would have a major impact on sponsorship and membership.
Also at Friday's announcement:
* Roos said one of his first priorities will be trying to convince players Colin Sylvia and Jack Watts to stay.
* Jackson said the club had applied to the AFL for a priority draft pick and was adamant the Demons needed one. But he also conceded the controversial tanking investigation earlier this year clouded the issue.
* The appointment of a football director is the "last domino" in their administration, according to Jackson.
* Roos said ultimate success is a few years away for Melbourne, but added the succession plan meant the players would know who their coaches would be for the next five to 10 years.
* Melbourne will honour the contracts of all football department staff, including interim coach Neil Craig. He is also free to leave if he wishes. Jackson also praised Craig for his work as stand-in coach.
* Roos is prepared to trade away their No.2 draft pick, especially for a midfielder. He said the midfield is Melbourne's glaring on-field weakness.
* The new coach has signalled a big change in game style, with a focus on defensive transition running.