Cley was actively engaged in trade by 1387, when a man from Walsingham, Norfolk, was pardoned his outlawry in the county for failing to appear to answer his suit for a debt of £3. He occasionally shipped cloth to the Low Countries, and imported grain, wine and salt, but his principal trade was in herring. In his ventures as far as Spain and Gascony, he sometimes made use of a vessel owned by his kinsman, Robert Cley (d.1416). The fish trade brought Cley and his fellows into contact with markets widely dispersed through the kingdom: in 1407, for instance, he was being sued for debt by a man from Salisbury.
Cley had considerable experience of public service locally: he was elected bailiff seven times in all, and as such is recorded making returns to the Parliaments of 1399, 1407, 1411 and 1414 (Nov.). At the elections to the Parliament of 1419 he stood surety for William Colkirk.
