Following Andy Aitken's departure in February 1909, Boro had been managed by secretary-manager John Gunter for sixteen months before Walker signed on 27 June 1910.
Soon after his appointment, he was in trouble for illegally approaching one of his former Airdrie players to try to convince him to sign for Boro.
In December 1910, chairman Thomas Gibson-Poole, the local Conservative Party candidate, believed that if Middlesbrough beat Sunderland in the derby game at Ayresome Park two days prior to the election, it would improve his chances of winning.
Before the game took place, Walker offered Sunderland captain Charlie Thompson £30 to throw the match, but he rejected and reported the matter to his chairman who subsequently informed the Football Association.
On 16 January 1911, an FA Commission decided that money had been offered and both Walker and Gibson-Poole were suspended from football for life.