In 1292 he inherited the Okehampton estates from his father. In 1293 he inherited the unalienated portions of the Reviers estate, also from his father. He was created 1st Lord Courtenay [England by writ] on 6 February 1298/99. He fought in the Siege of Carlaverock in 1300. He was invested as a Knight in 1306. He was invested as a Knight Banneret in 1308. He held the office of a Lord Ordainer in 1313. He held the office of Warden of Devon and Cornwall Coast in 1324. He was created 1st Earl of Devon [England] on 22 February 1334/35. He held the office of Warden of Devon and Cornwall Coast in 1336.