Ernest Greenleaves was born in Heaton Moore, Lancashire, England in on 8 May 1868. He was articled to Thomas Stevens (1849-1937) in Bournemouth, Dorset from 1884 to 1888 and remained with him as his assistant until 1893. He also attended Bournemouth School of Art. He worked as an assistant to J. Moore in 1893-94; to L. D. P. Way from 1895 to 1897; to Frederick William Albury (?-1912) in Reading, Berkshire in 1898; to J. Cooke in Eastbourne, Sussex in 1899; to Joseph Barker Daniel Wall (1849-1923) in Bexhill, Sussex in 1899; to C. H. Burstow in Horsham, Sussex in 1899-1900; to Henry Ward (1854-1927) in Hastings, Sussex in 1900-01; and to Thomas Richard Phillips in Pontypridd, Glamorgan, Wales from 1901 to c.1916.
Greenleaves subsequently practised as an architect in Pontypridd. By 1920 he had relocated his practice to Weston-Super-Mare, Somerset. He also lectured on Building Construction at the Science and Art School, Weston-super-Mare. He was elected a Licentiate of the Royal Institute of British Architects (LRIBA) in 1911. He was also an Associate of the South Wales Institute of Architects He died on 31 January 1941. His death was registered in Weston-Super-Mare, Somerset
National Schools, Newtownards, Co. Down; Co. Antrim Yacht Club, Whitehead; National Schools, Springfield Road, Belfast; Parochial Hall and Club, Cambridge, Co. Down; Police station, Arundel; Board School, Seaford; Forest Hotel, Welsh Harp Hotel, and Ynishir Hotel, Glamorgan; Bargoed Cinema; St. John's Church, Bournemouth Cemetery Chapel, Horsham; associated in competition work for Undercliff Drive and two piers at Bournemouth.
Directory of British Architects 1834-1914. Compiled by Antonia Brodie, et al. Volume 1: A-K. London; New York: British Architectural Library, Royal Institute of British Architects/Continuum, 2001