[7] Walker's ordained ministry began as a curate at St Mary Handsworth, after which he was a team vicar at Maltby, then Bramley before ordination to the episcopate.

Walker was consecrated as a bishop on 30 November 2000 by George Carey, Archbishop of Canterbury,[8] at St Paul's Cathedral.

[13] Walker was awarded a doctorate in 2014 after research, at Warwick University, on how people belong to their churches, particularly in rural Anglicanism.

[17] In November 2023, he was one of 44 Church of England bishops who signed an open letter supporting the use of the Prayers of Love and Faith (i.e. blessings for same-sex couples) and called for "Guidance being issued without delay that includes the removal of all restrictions on clergy entering same-sex civil marriages, and on bishops ordaining and licensing such clergy".

[19] He married Susan in 1980 and together they have two children;[4] he ordained her deacon at Manchester Cathedral on 1 July 2018, to serve as assistant curate in Prestwich.