Sedgrave, Walter (1546–1621), catholic merchant and alderman of Dublin, was the eldest son of Christopher Sedgrave (d. 1589) and his wife Alice, daughter of Nicholas Humphrey, alderman of Dublin. The Sedgraves were part of Dublin's merchant elite, holding considerable property and being closely connected with the gentry of the Pale. Christopher was an influential and respected figure in the community, and lent extensively to the government. As mayor of Dublin (1559–60) he had opposed the reintroduction of the reformation in Ireland and had championed catholicism long before it was fashionable to do so. Walter assumed his father's place among the city's political elite, holding a number of offices in the city administration: sheriff (1577–8), alderman (1580–1621), mayor (1588–9), and treasurer (1591–2). He too lent to the government, and also inherited his father's catholic zeal, patronising priests and being (1592–8) head of the Fraternity of St Anne's, a powerful secret catholic brotherhood. Nonetheless, he did not scruple to purchase the dissolved lands of the monastery of St John the Baptist in Dublin. He owned four houses in Dublin and a mansion in Cabra, as well as extensive lands in Co. Meath and Co. Dublin.
He was heavily involved in preparations for the rebellion of James Eustace (qv), Viscount Baltinglass, in defence of the catholic religion, which erupted in south Co. Dublin in June 1580. From May he had been in close contact with Eustace and other conspirators, furnishing them with arms. Implicated in June 1583 by the testimony of one of Eustace's servants, he was imprisoned in Dublin castle. On 30 June the citizens of Dublin petitioned that he and another accused be placed in the custody of the corporation, citing a fifteenth-century statute whereby all holders of the franchise could be tried only by the city government. The government's legal counsel reluctantly concurred and the two men were handed over. Unsurprisingly, they were swiftly judged innocent and freed. Further investigations revealed Christopher Sedgrave's complicity in the revolt, but the authorities realised that they had little chance of securing his conviction and suppressed this information. In April 1584 the government was still exploring avenues for prosecuting Walter, but he was restored to favour by September 1585, when he was licensed to import cloth from Chester.
When the government resolved on a crackdown against recusancy in late 1605, Walter was among a number of prominent Palesmen who were brought before the lord deputy and council and commanded to attend Church of Ireland services. They refused, arguing it was contrary to their conscience. On 22 November he was fined £100 sterling in the court of Castle Chamber and imprisoned for a period. In March 1606 a search of his house by the authorities apparently yielded a letter from the pope to the Dublin catholics, assuring them of military aid. Despite his travails with the central administration, he remained an integral part of the Dublin corporation and in December 1611 was appointed to a subcommittee for deciding who should represent the city in the upcoming parliament and for proposing bills. He died 10 December 1621, leaving a fund for the education of priests in his will.
He married (a.1590) Eleanor, daughter of Bartholomew Ball, alderman of Dublin, who predeceased him by less than three weeks; they had two sons and three daughters.