Warner, a native of Gimingham (between North Walsham and Cromer), entered the freedom of Norwich in 1383-4, and was elected to the first of his civic offices within two years. In 1390-1 he contributed 20s. towards the cost of having the wool staple at Norwich, it being clearly in his own interests as a merchant to do so. He is known to have traded in canvas, madder, wax and salt: commodities which were brought into Great Yarmouth in ships from France and the Low Countries; and to have made several shipments of cloth through the same port.
Besides his tenure of office as bailiff (three times), sheriff and mayor, Warner was occasionally required to undertake other tasks on behalf of the community. Thus, early in 1399, when Richard II was expected to visit Norwich, he was named on the committee of citizens assigned to prepare the case to be put to the King in order to procure a new charter under which Norwich would become a shire-incorporate.
