This street was called after Douglas Haig, 1st Earl Haig.
"Resolved – That the names Earl Haig Park, Earl Haig Crescent, and Earl Haig Gardens be approved for new streets on the property of the Irish Sailors’ and Soldiers’ Land Trust, situated off Woodstock Road". (18th March 1931).
For more information: https://www.nam.ac.uk/explore/douglas-haig