Scotland was initially given guernsey No. 44, and he switched to No. 29 in 2001. He made his debut in Round 3 of 1999 and played twelve senior matches in his debut season, including Collingwood's Round 22 match, which was the last game it ever played at its traditional home ground, Victoria Park. He played another ten in 2000, but managed only two senior games in 2001 - in the first and last rounds of the season. His performance in that final round match, to that stage a career-best with twenty-eight disposals, arguably saved his Collingwood career, with coach Mick Malthouse stating that he had matured considerably as a footballer over that season. Scotland became a regular for the Magpies in 2002, playing 19 matches through the season, including fourteen consecutively after Round 12. He played in all of Collingwood's finals matches, including the Grand Final loss against Brisbane. In 2003, he fell out of favour again, playing only sporadically throughout most of the season; however, he gained selection again in Round 20, and played every game for the rest of the year, including another Grand Final loss against Brisbane, which was his last game for Collingwood. In his five seasons at Collingwood, Scotland was generally characterised as a midfielder or half-back flanker at a club which had several players of similar ability capable of filling that role; he therefore struggled to be a regular member of coach Mick Malthouse's regular 22. Scotland decided that his long-term opportunities at Collingwood would be limited under Malthouse, and after discussions with Carlton coach Denis Pagan, he requested to be traded to the rival club at the end of 2003. He had previously considered a move to the Kangaroos after playing only two games in 2001.
Carlton
At the end of the 2003 season Scotland was traded to Carlton in exchange for a third round draft pick in the 2003 AFL Draft. Even at the time, the trade was considered to be good value for Carlton, He was given the No. 29 guernsey, the same number he had worn at Collingwood. Scotland was a regular player throughout most of his time at Carlton. He played 11 seasons with the club and appeared in every game in five of those seasons. As at Collingwood, Scotland played generally as a midfielder, rotating into a sweeping half-back role. In Round 9, 2005, Scotland played in Carlton's team in the last game it ever played at its traditional home ground at Princes Park; he had previously played in Collingwood's last game at its traditional suburban home, making him the only player to appear in both of these historic matches. In 2006, Scotland finished third in the Robert Reynolds Trophy, and had the second-most disposals of any player in the AFL. He improved again in 2007, collecting a career-high 41 disposals in a match in Round 22 against, finishing a close second for the Robert Reynolds Trophy, and polling a club-high 12 Brownlow Medal votes. In the young Carlton teams he played in, Scotland was one of the most experienced players. He featured in the club's leadership group from 2007 until 2010, before voluntarily stepping down in 2011. He continued to play reliable football through this time. In 2011, Scotland played his 200th game and became the oldest player on the Carlton list, turning 31 during the year; in spite of this, 2011 was widely regarded by pundits as Scotland's best season to date; he was nominated in the 40-man squad for the All-Australian team, but did not make the final team, and he finished 4th in the John Nicholls Medal. He was awarded life membership of the Carlton Football Club in December 2011. Scotland played consistently well again in 2012, and although he attracted less wider acclaim around the league, he won the John Nicholls Medal for the first time in his career. In 2014, at age 33, Scotland was moved from Carlton's senior list to its rookie list, by being delisted and then redrafted as a rookie. He played four games off the rookie list, before announcing his retirement from the AFL on 20 May 2014, citing a degenerative ankle complaint. Scotland was described by Tony Shaw, who coached him in his first season with Collingwood, as a truly skilful player, capable of kicking on with both feet, with good durability and a good football brain.
