Following Milton Keynes Dons' appointment of Karl Robinson as manager in 2010, the club created a recruitment division and named Mitchell as the club's first Head of Recruitment.[17] He was notably responsible for the signing of former England international Alan Smith.[18]
In January 2012, Mitchell joined Championship club Southampton as Head of Recruitment.[19] The club gained promotion to the Premier League in his first season and Mitchell began working with Mauricio Pochettino following his appointment in January 2013. He oversaw the signings of players including Nathaniel Clyne, Maya Yoshida, Paulo Gazzaniga and Steven Davis.[20][21][22][23]
Following Pochettino's move to Premier League rivals Tottenham Hotspur, Mitchell completed his switch in November 2014 to link up with the manager.[24] He helped the club sign players such as Dele Alli, Son Heung-min, Kieran Trippier and Toby Alderweireld.[25][26][27] In August 2016, reports suggested Mitchell was to leave the club "after his dream job turned into a nightmare" and he had fallen out with chairman Daniel Levy.[28] In December, it was revealed Mitchell was serving his 16-month notice period.[29]
In February 2018, Mitchell was named Head of Recruitment and Development by Bundesliga club RB Leipzig.[30] In his first transfer window with the club, Mitchell helped sign Matheus Cunha and Nordi Mukiele, as well as Arsenal youth prospect Emile Smith Rowe on loan. Mitchell attracted interest from several Premier League clubs throughout 2019 and was heavily linked to a move to Manchester United.[31][32]
Reports suggested he could be offered an expanded role as Technical Director to oversee Red Bull's global football – including FC Liefering, Red Bull Salzburg and the New York Red Bulls[33]
In June 2020, Mitchell joined Monaco as sporting director.[34][35]