 He became the King's Justiciar, High Sheriff of Kent from 1189 to 1193 and 1196 to 1215 and High Sheriff of Surrey from 1213 to 1215.In 1215 he was sent to Lancaster to also take over as High Sheriff of Lancaster following the revolt of Gilbert Fitzreinfrid.Cornhill was in charge of collecting the tax of a fifteenth on merchants' imports and exports from 1202 to 1204, when he, along with his fellow keepers William of Wrotham and William of Furnell, accounted for the revenues on the Pipe roll of 1204.