Cambridge United Morrison was born in
Bury St Edmunds, Suffolk. He grew up in nearby
Haverhill, and attended
Castle Manor School. He started his football career with
Cambridge United, where he came through their youth academy and at the age of 15 became the youngest player to ever feature for their reserve side. He made his debut for Cambridge United in October 2005 against
Halifax Town when he was aged 17, He appeared for
England Cthe team that represents England at semi-professional levelagainst Finland in November 2007 and against Wales in May 2008 when England retained the
Four Nations Tournament title.
Leicester City Morrison joined
Leicester City on 2 July 2008, signing a two-year contract for an undisclosed fee. Pleased at joining Leicester, Morrison believed his transfer was in the best interests of Cambridge, who could have lost him on a free transfer. He saw manager
Nigel Pearson as his mentor due to his past experience as a defender. Morrison made his professional debut in a 2–0 win over
Milton Keynes Dons on 9 August, and scored his first goal in a 4–2 win over
Huddersfield Town on 24 January 2009. He returned to the first-team line-up in November 2008 after
Patrick Kisnorbo was ruled out by injury. Helping Leicester win promotion as champions, he ended their last home game of the season by scoring two goals against
Scunthorpe United on 24 April, the night they received the League One trophy. in a pre-season
friendly, July 2010 Happy to fight for a first-team spot in the 2009–10 season, Morrison's squad number was changed from 15 to 4. On 6 October 2009, Morrison signed a two-year contract extension with Leicester, to run until June 2012. He scored his first goal of the season in a 2–1 home win over
Sheffield United on Boxing Day. Morrison took over the right back role in January 2010, after a poor display from teammate
Robbie Neilson.
Sheffield Wednesday On 7 January 2011, Morrison signed for
Sheffield Wednesday on a three-and-a-half-year contract for an undisclosed fee.
Charlton Athletic On 12 July 2011, Morrison joined League One side
Charlton Athletic on a three-year contract for an undisclosed fee. He quickly established himself as a key member of Chris Powell's team, winning
League One Player of the Month for November 2011. He established himself as the team's first choice centre-half during the 2012–13 Championship campaign, in which the Addicks finished in ninth place. On 24 June 2014, Morrison signed a two-year contract extension, keeping him at the club until 2016.
Birmingham City in 2016 Morrison joined
Birmingham City on 31 October 2014 on a two-month emergency loan. He went straight into the starting eleven for the following day's goalless draw at
Wolverhampton Wanderers, and kept his place thereafter, establishing himself as centre-back of choice alongside captain
Paul Robinson. In December, it was announced that Morrison would sign a three-and-a-half-year contract with Birmingham once his loan ended and the January transfer window opened. His loan was initially extended for a few days to ensure his eligibility for the third-round FA Cup tie against
Blyth Spartans, when he captained the team, and the permanent move was confirmed on 5 January 2015. Morrison left the club after his contract expired in June 2019, after failing to agree a new deal.
Reading On 19 July 2019, Morrison joined another Championship club,
Reading, on a two-year contract. He scored his first goal for the club to complete a 2–0 league win against
Huddersfield Town on 24 August.
Portsmouth On 26 July 2022,
Portsmouth announced the signing of Morrison on a one-year contract.
Cambridge United On 26 January 2023, Morrison re-joined
Cambridge United, on a one-and-a-half-year contract. ==International career==