Erroll Victor McGaw was born in the Spring of 1882 in Aldershot, Hampshire, England and was baptised in Folkstone, Kent on 28 May that same year.

He was the son of Robert McGaw (b. 1858) and Ellen Wills Boxer (b. 1859); little is known about his father but his mother is known to have hailed from Folkstone, Kent and married McGaw in Farnham, Surrey in 1880. He had two known siblings: Robert William (1880-1941) and Agnes Isabella (1884-1976, later Mrs Reginald Emmanuel Boundy).

Erroll's father Robert died in London in 1887 and his mother began a relationship with James Oliver Watson (b. 1849), a boot-maker from Southampton; from this union Erroll acquired a half-sibling, Ivy Marguerite (b. 1890) and his mother and Watson were eventually married in 1898.

Erroll first appears on the 1891 census living with his mother, step-father and siblings at 20 St John's Street in Folkstone but the family later resettled in Southampton, appearing on the 1901 census at Ivy Cottage, Ash Tree Road, South Stoneham but Erroll was absent, his whereabouts at the time being unclear but he was presumably already at sea. His step-father died in April 1911.

He was married in mid-1902 to Mary Anne Frances Clarke (b. 29 November 1882), a native of St Denys, Hampshire. Together they would have three children: Florence Ellen "Nellie" (b. 27 December 1903), Erroll Frederick (b. 24 March 1905) and Dorothy Mabel (29 March 1909). The 1911 census shows the family living at 30 Queenstown Road, Freemantle, Southampton and McGaw's profession is described as a baker's van man for a cooperative.

When he signed on to the Titanic on 6 April 1912 McGaw gave his address as 6 Broadlands Road, Southampton and his previous ship as the Oceanic and as a fireman he could expect monthly wages of £6.

Erroll McGaw died in the Titanic disaster and his body, if recovered, was never identified. 

His widow Mary Ann was never remarried; she continued to live in Hampshire and died in Winchester in 1971 having been a widow for nearly 60 years. Erroll's children also all remained in Hampshire; Florence Ellen was married in 1928 to Herbert Dacombe and she died in 1987 in Winchester. Erroll Frederick was married in 1930 to Violet Nother; he died in Southampton in 1988. Dorothy Mabel was married in 1933 to Albert Yarney; she died in 1983 in Winchester. 

His brother Robert also met his demise at sea; also a merchant seaman, he continued serving into his 60s and was aboard the SS Derrynane, working as a greaser, when that ship was attacked and sunk on 12 February 1941.