A versatile key-position player, Roos was a strong mark who was excellent at ground level, and in his prime was rated the best footballer in Australia.

He has won many accolades throughout his career: he was named All-Australian seven times; received the league's most valuable player (MVP) award; and represented Victoria on 14 occasions in State of Origin.

Roos made his senior VFL debut for Fitzroy in Round 4 of the 1982 season against Sydney, the club he would eventually move to 13 years later.

The club administration started the search for a new coach and it is widely believed that negotiations with Terry Wallace were at an advanced stage.

Nevertheless, when Eade finally went with several games of the minor round still to be played, Roos was appointed caretaker senior coach for the remainder of the 2002 season, a move hugely popular with Swans fans, who remembered his great contribution to the club as a player.

Surprisingly, the Swans won most of their remaining games that year (six of their last ten), and the fans soon let it be known who they wanted as coach by reviving the famous "Roooos" call.

The administrators knew when they were beaten, and appointed Roos as full-time senior coach for the 2003 season (despite reportedly having to pay Wallace a considerable amount to unwind their almost-concluded deal with him).

[11] Roos also implemented a policy of giving up first round draft picks in exchange for players from other clubs: namely, Darren Jolly, Ted Richards, Peter Everitt, Martin Mattner, Rhyce Shaw and Shane Mumford in the years 2004–2009 inclusive.

Coincidentally, in the 2005 AFL Grand Final, the Sydney Swans under Roos, would also kick 8.10 (58), this time defeating the West Coast Eagles which scored 7.12 (54) to win the premiership.

[5] In the 2006 pre-season, Roos briefly returned to the US with his Swans side for an exhibition match against the Kangaroos at UCLA, and suggested that this should become an annual event.

[11][5][19][20] On 6 September 2013, Roos was appointed senior coach of the Melbourne Football Club on a two-year contract, with the option of a third year.

[28] However, in Round 21, 2014, Roos and the Demons came under fire after suffering a 64-point defeat to an injury-hit Greater Western Sydney side which could only operate a one-man bench in the entire second half.

[29] In the 2015 season, Melbourne Demons under Roos finished in thirteenth place on the ladder with seven wins and fifteen losses.

[26] In the 2016 season, Melbourne Demons under Roos finished in eleventh place on the ladder with ten wins and twelve losses.

In addition, he had several football-related media roles, including writing for the Herald Sun and doing match day analysis for Fox Footy.

Despite informal inquiries from other clubs like West Coast,[32] Adelaide,[33] Melbourne,[34] Gold Coast,[35][36] Carlton,[37] and the successor to his old club Fitzroy, the Brisbane Lions,[38] Roos had repeatedly insisted he has no intention of coaching another AFL club[39][40] Roos was critical of the substitute rule which was introduced by the AFL in 2011, claiming that the rule, which aimed to lessen injuries resulting from collisions, could have the opposite effect of forcing injured players to stay on the field: The thing that concerns me the most is you can interchange a guy in the third quarter so he comes off, can't come back on again, and you get an injury in the last quarter of the game and you've got a healthy player sitting on the bench doing nothing and an unhealthy player still in your rotations.

[44] They have two sons, Dylan and Tyler, the latter of whom appeared on The Amazing Race Australia in 2019[45] and is currently dating American tennis player Amanda Anisimova.

[46][47][48][49][50] In September 2003, Roos ruptured his Achilles tendon during a game of social basketball, and was seen on crutches during the Swans' qualifying final win over Port Adelaide at AAMI Stadium the following weekend.

[51] In 2008 he was named Australian Father of the Year in recognition of his ability to balance the needs of his family with the responsibilities of managing a high-profile sports team.