Born in Waterloo, Lancashire and educated at the Liverpool City School of Art, where he acquired the nickname Josh.
Painted film-posters, magazine and (especially) book covers. Creating a total of over 400 cover paintings, his personal preference was for science fiction jackets (for example see Robert Silverberg's Majipoor novels and Kirby's own Voyage of the Ayeguy) but his work on the covers of Terry Pratchett's Discworld series of novels is well known. Worked almost exclusively in oils.
Died in Shelfanger near Diss in Norfolk His death was unexpected but of natural causes, he died in his sleep aged 72.