On 23 November 2012, the Richmond Football Club announced Cotchin's appointment as club captain for the 2013 season. With this appointment he became the 40th captain in Richmond’s AFL/VFL history. Cotchin chose to continue wearing his No. 9 jumper instead of adopting the recent practice of captains switching to No. 17 as a tribute to Richmond legend Jack Dyer who wore the number 17 and who died in 2003. The three captains prior to Cotchin, Wayne Campbell, Kane Johnson and Chris Newman all adopted the number in honour of Dyer. Cotchin explained that he held the club's history and Dyer in high regard but he had decided to keep the No. 9 because he has worn it throughout his football career including his junior years.
Cotchin helped lead the Tigers to their first finals appearance in 12 years and also lead the Tigers in amazing fashion to the finals in 2014 after they slumped to 3-10 and equal last on the ladder.
Cotchin struggled with injury heading into the 2008 AFL season and was put onto the long term injury list. He was declared fit to play by Round 4 and subsequently played three matches for Richmond's VFL affiliate side Coburg Tigers.
Cotchin made his senior debut against Geelong in Round 8, coming in as a replacement following the late withdrawal of Adam Pattison. He picked up 16 possessions and kicked 2 goals, one of them with his first kick. In his debut match Cotchin played mainly up forward with a few stints on the ball.
After further impressive performances, Cotchin received the AFL Rising Star nomination for Round 12. At season's end he finished third in the AFL Rising Star Award with 21 votes, behind DockerRhys Palmer topped the poll with 44 votes, one off the maximum, ahead of Hawthorn'sCyril Rioli with 37.
Cotchin again struggled with injury, but after missing the first seven Rounds, he came back to play Port Adelaide in Round 8 but struggled to have an impact collecting only 9 disposals. His season came to an end due to a hip injury suffered against the Melbourne in Round 18. Cotchin finished the season averaging 17.7 disposals and kicking 9 goals.
Cotchin had a fine start to the season but dropped off a bit after Round 11 and then a suspension against North Melbourne for charging ruled him out for four games. He came back for the last two games against St Kilda and Port Adelaide, achieving 22 disposals against them both and kicking two goals against them both.
Cotchin started the season strongly averaging 23.6 disposals and kicking 8 goals in the first half of the season, and finished even better in the second half of the season averaging 24.5 disposals and booting 10 goals. He played in all 22 games and his efforts won him his first Richmond best and fairest award, the Jack Dyer Medal, the Yiooken Award for best on the ground in the Richmond versus Essendon Dreamtime at the 'G game and 15 Brownlow Medal votes.
2012 saw Cotchin in his best season in his career to date, playing all 22 games and winning his second Jack Dyer Medal as well as the AFL Coaches Association (AFLCA) Champion Player of the year award and a place in the All-Australian team, on the wing. He collected 606 disposals (eighth in the AFL) and kicked 21 goals. His best game this season came against the Western Bulldogs, collecting 35 disposals and kicking 3 goals in a best on ground performance. He also received 26 Brownlow medal votes for the season to finish equal second for the award with Sam Mitchell from Hawthorn.
This was the year that Cotchin was first appointed as the captain of Richmond. He played in 22 games for the third season in a row and averaged 26 disposals per game. He finished fifth in the Richmond Best & Fairest (Jack Dyer Medal) and won the Kevin Bartlett Medal for that effort.
Cotchin was reappointed as club captain with Brett Deledio reappointed vice-captain. Cotchin won his third Jack Dyer Medal, becoming the equal second youngest player in AFL history to have won 3 Best and Fairest awards.
In December 2013, Cotchin married his long-term girlfriend Brooke Kennedy in a ceremony at Flinders, Victoria. On 20 March 2014, they announced they are expecting a baby. The couple's first daughter Harper Foxx Cotchin was born in September 2014. 
^[year=2012&tx_ttnews[month]=11&tx_ttnews[tt_news]=448&cHash=6e6d238af6a90ebc0e54058fcceed7ae "Cotchin named Richmond captain"]. Northern Football League. Northern Football League. 28 November 2014. Retrieved 24 March 2014.