Morris was born in 1873 at Lee in Blackheath, at that point part of Kent.
His father, also William, was a solicitor and Morris followed him into the profession after attending St Mark's School in Windsor.
He played occasionally for the Gentlemen of Kent and made another double hundred for Dulwich Cricket Club in 1896.
His debut came against MCC at Lord's, with his second match against Nottinghamshire in the County Championship at Beckenham.
He failed to reach double figures in either match, with a highest first-class score of six runs.