French, Sir Oliver (d. 1666), merchant and mayor of Galway, was a son of Patrick French and grandson of Oliver Oge French, mayor of Galway in 1596. The French family, one of the fourteen ‘tribes’ of Galway, were catholics of Anglo-Norman origin, who first settled in Ireland in Co. Wexford and were resident in Galway city by the year 1425. On a 1651 map of the city, Oliver French's house on North Street was listed as one of those belonging to the principal gentry and citizens of Galway. During the 1640s he held various civic appointments in the city. By 1641 he was a burgess of Galway and member of the city council. In 1643 he was elected as sheriff and, on 18 June 1647, he was one of twelve men chosen to view the book of excise.
French acted as an agent for the confederate supreme council to the United Provinces in May 1648, where he made a speech at the states general in The Hague. In his speech he outlined the reasons behind the war in Ireland, the justness of the confederate cause and the many disadvantages they had to overcome. In October 1648 he petitioned Prince Charles to intervene with Ormond (qv) on his behalf, to enable him to retain his lands. On the basis of French's loyalty, the prince recommended his case.
French was mayor of Galway city from September 1650 to September 1651, during which time he was knighted by Clanricarde (qv), then royalist lord deputy. As a member of the city council, he was involved in communications with the Cromwellian Henry Ireton (qv), in November 1651, regarding possible terms for the surrender of the city. In 1652 he acted as an agent from the city to Sir Charles Coote (qv) and was described by the author of Aphorismical discovery as one of the mutinous people within Galway city. In 1653 French was dispossessed of his property in the city by the Cromwellian commissioners and, on 1 July 1656, he was transplanted to Co. Mayo, where he received 1,694 acres in the barony of Kilmaine. He died in 1666 and his eldest son, Patrick, receiving a confirmatory grant of these lands in 1677, changed the name of the property from Cloughanearla to Frenchbrook.
French was twice married; his second wife, Eveline (née Brown), whom he married after 1648, was the widow of Robert French of Monivea. In March 1650 he arranged the marriage of Christicke, a daughter from his first marriage, to Patrick French, eldest son and heir of his second wife's marriage to Robert French.