[3] While with Newcastle United reserves, Morris and teammate Darren Lough were described by coach Adam Sadler as "the next big thing",[4] but he was released by the club in 2010, having never featured in the first team.

[9][10] After making five appearances for Blyth, Morris left the club to join the Glenn Hoddle Academy in Spain.

[11][12] While at the Glenn Hoddle Academy, Morris also played for Spanish Fourth Division side Jerez Industrial CF, where he gained full-time, senior football experience.

[14] Following unsuccessful trials in England, Portugal and Greece, Morris had considered giving up professional football[15] before signing for Dunfermline Athletic in the Scottish First Division on 31 August 2012.

[23] In his second season at Dunfermline Athletic, Morris rejected rumours that he had left the club by appearing in the opening friendly against Hearts.

[35] Having established himself in central defence alongside Jarosław Fojut, Morris soon suffered an Achilles injury during a match against St Johnstone which kept him out for several weeks.

[37] He scored in the next game, in the semi-final of the Scottish League Cup, which saw Dundee United beat Aberdeen 2–1 to send them through to the final.

[38] Morris then injured his knee,[39] but recovered in time to start in the League Cup Final as Dundee United lost 2–0 to Celtic.

[47] Prior to the start of the 2017–18 season, Morris was named captain of the club,[48] following the departures of Andy Geggan and Callum Fordyce.

[53][54] Although born in England, Morris has Irish ancestry through both his parents, his mother's family originating from Waterford and his father's from Belfast.

On 31 August 2016, Morris was called up for the first time to the Northern Ireland squad for the World Cup qualifying game against the Czech Republic.