He made 79 appearances for Birmingham, before suffering a series of injuries during the 2012–13 season that prevented him from playing again, leaving the club in August 2013 by mutual consent.

King has served three jail sentences,[2] and has a number of other criminal convictions including: theft from a person and from a car, criminal damage, and attempting to obtain property by deception; fraudulent use of vehicle licence document, driving without insurance, speeding, drink driving; a wounding incident while playing amateur football, and two cases involving assault of young women rejecting his advances in the Soho area of London.

King had his playing contract cancelled by Wigan after being convicted of the sexual assault charges and being sentenced to eighteen months in prison.

[4] In May 2002 King was jailed for 18 months for driving a stolen car, but returned to the Gillingham team in October 2002 after he was released on appeal.

He played in the second leg, and in the final against Leeds United, which Watford won 3–0 to win promotion to the FA Premier League.

[18] The injury kept him out of action for six months, and he did not return until 14 April 2007, when he came on as a substitute in the 4–1 FA Cup semi–final loss to Manchester United at Villa Park.

With Watford topping the table for much of the first half of the season, King scored ten goals before the end of 2007, including five in successive games in October.

[26] In August 2008, Premier League newcomers Hull City bid an undisclosed amount for King, which Wigan accepted.

[29] King's loan at Hull was cut short after he reacted in an "unacceptable manner" when told he was not in the starting line-up for a match against Arsenal, and he was sent home rather than taking his place among the substitutes.

[22] Upon his release from jail former manager Aidy Boothroyd invited King to train with Coventry City to regain his fitness.

[35] However, on 10 June 2011, he agreed a three-year contract with Birmingham City, citing the opportunity to play in the Europa League as a major factor in his decision.

[38] He suffered knee ligament damage in pre-season training which delayed his Birmingham debut until 11 September, when he played the last half-hour of a 3–0 home win over Millwall.

[47] However, in March, his season was brought to a premature close due to a long-term knee injury deteriorated, requiring an operation.

[48] On 28 August 2013, it was announced that Marlon King would be leaving Birmingham, after his contract was terminated by mutual consent in order to reduce the club's wage bill.

[51] Having made his United debut in a 1–0 home loss to Preston North End,[52] he scored his first goal for his new club two games later in a 1–1 draw with Crawley Town at Bramall Lane.

[53] King quickly fell out of favour following the arrival of new manager Nigel Clough however, and following a spell on the sidelines due to a knee injury he was released in December 2013.

[54] In 2004 King played an important part in Jamaica's unsuccessful attempt to qualify for the 2006 World Cup, scoring six goals in eight games.

King also played for Jamaica in a friendly against Trinidad and Tobago scoring a goal and captaining the team in the absence of Ricardo Gardner due to injury.

[65] After the resignation of Theodore Whitmore, new coach Winfried Schäfer recalled King to the team for the World Cup qualifiers in September 2013.

His solicitor commented that "His reputation will be tarnished forever, whatever success he achieves, he'll always be referred to in a Tyson-esque way as someone who has had a criminal past and that is a considerable penalty.

[6] In December 2008, again in the Soho area, King was arrested on suspicion of punching a 20-year-old female university student in the face, causing a broken nose and split lip for which she was treated in hospital.

[25] King's agent, Tony Finnigan, said he was confident that his client would find a club on his release,[73] and accused the Professional Footballers' Association (PFA) of failing to offer support.