He attended the Downs Malvern in Colwall and Canford School in Dorset, and read English literature at University College London.

He began a career in literary journalism while working in the Design Centre's bookshop in the 1980s, contributing regular book reviews to Gay News and The London Magazine.

Parker subsequently turned to writing non-fiction, and his first book, The Old Lie: The Great War and the Public-School Ethos[4][5] was published by Constable in 1987.

[9][10][11][12] He edited (and wrote much of) two literary encyclopaedias: A Reader's Guide to the Twentieth-Century Novel[13][14] published in the UK by Fourth Estate and Helicon in 1994[15] and in America by Oxford University Press in 1995, and A Reader's Guide to Twentieth-Century Writers[16] published in the UK by Fourth Estate and Helicon in 1995[15][17] and in America by Oxford University Press in 1996.

[19] David Thomson, in The New Republic described it as, "Immense and magnificent … A Life Revealed is a modest subtitle for such a daunting process of reconstruction and re-appraisal.

[38] A full-length animated feature film of J. R. Ackerley's book My Dog Tulip, for which he collaborated on the script and acted as advisor to the producers, was released in 2010.