 From 1573 to 1578 he was Shropshire's commissioner in matters as diverse as oyer and terminer, a key function in managing the judicial system, for sewers, and for the survey of tanneries.When Walter Devereux, 1st Earl of Essex, a key territorial magnate in the region, died in 1576, his will appointed Corbet one of a group of officials to act as feoffees of his estates.In 1575, when Sidney departed for the second time to take up the position of Lord Deputy of Ireland, he invested Corbet formally as vice-president of the Council in the Marches.