[3] New manager Serge Romano identified Johnson as one of the club's more saleable assets and agreed that he could leave if a suitable offer materialised.

[5] He then played in a pre-season game for English club Plymouth Argyle,[3] and joined permanently for an undisclosed fee on a three-year contract a few days later.

[16] In late-2023, Johnson joined Cardiff City as a coach on placement,[17] taking the club's under-15 side to victory in the regional floodlit cup final.

[18] On 5 January 2011, Johnson appeared in court charged with false imprisonment of a woman whilst at the house of an unnamed Blackburn Rovers player.

[19] The case was dropped due to lack of evidence at his return to court on 7 April 2011, with Johnson later talking of his innocence and relief that his name had been cleared.