In the summer of 2004, United manager Sir Alex Ferguson indicated Stewart had no future at the club and he was free to leave.
[7] Stewart failed to match expectations and at the end of a season disrupted by injury, Hearts allowed him to leave.
[7] Desperate for continuity and regular football, Stewart expressed his wish to stay in Edinburgh and signed for Hearts' rivals Hibernian after negotiating the end of his Manchester United contract.
Stewart was appointed Hearts club captain by manager Csaba Laszlo before the start of the 2009–10 season, following the departure of Robbie Neilson.
[17][20] Stewart played four matches during qualification for the 2004 UEFA European Under-21 Championship,[17] including the 1−0 win away to Germany in September 2003.
[29] On 17 April, he made his debut in the friendly against Nigeria;[30] he replaced Gareth Williams in the 64th minute of the 2−1 defeat at Pittodrie.
[31][32] He made his full debut the following month when he started against South Korea at the Asiad Main Stadium in Busan.
[30][33] He was replaced by Scott Severin at half-time as South Korea ran out 4−1 winners in their preparations for the 2002 FIFA World Cup.
[30][35] In August 2008, Stewart was recalled to the Scotland squad and won his first cap in over six years in the goalless draw with Northern Ireland at Hampden Park.
[38] He was suspended from appearing on BBC Scotland's football coverage in February 2020, following comments he made about Rangers media officer Jim Traynor.
On 11 February 2016, Stewart appeared on Thursday Focus on Man United's in-house channel MUTV discussing his life, career and politics.