Boumsong began his senior career with French club Le Havre in 1997 before joining AJ Auxerre in 2000.

Boumsong was born in Douala, Cameroon, and started his career with French team Le Havre before joining AJ Auxerre.

[citation needed] As a result, Boumsong joined Alex McLeish at Rangers in 2004 and signed a five-year contract.

[5][6] Boumsong quickly adapted to the Scottish game and showed his skill as a centre-back, leading to rumours that his stay in Glasgow may be shorter than expected.

Halfway through the 2004–05 season, Newcastle under new manager Graeme Souness, made an £8 million bid for him, which Rangers accepted in a deal that was finalized once the January 2005 transfer window opened.

[7] The £8 million transfer fee raised eyebrows,[8] as the player, being out of contract, had joined Rangers for free just months before, at which point Newcastle showed no interest in signing him.

This transfer is one of those about which the Stevens inquiry report in June 2007 expressed concerns: "There remains inconsistencies in evidence provided by Graeme Souness – a former manager of the club – and Freddy Shepherd – apparently acting in an undefined role but not as a club official – as to their respective roles in transfer negotiations."

[10] As regards McKay it stated: "Further to the key findings from the final Quest report published on 15 June 2007 by the Premier League, Quest would like to emphasise that, in that report, it was clear that no evidence of irregular payments was found in the transfers in the inquiry period which involved the agent Willie McKay.

[citation needed] On 24 January 2008, Boumsong moved to French club Olympique Lyonnais on a three-and-a-half-year contract.

[citation needed] On 30 July 2010, Boumsong transferred from Olympique Lyonnais to Superleague Greece champions Panathinaikos F.C.

[citation needed] Boumsong appeared in only one game during Euro 2008, when during the group match between France and Italy he substituted Samir Nasri.