Mortimer encouraged and enabled Adam to eventually study at Oxford, where he obtained his doctorate and became extraordinarius in Canon law.
Adam left Oxford and practised his profession for seven years as an advocate in the archiepiscopal court of Canterbury, 1390–1397, sitting on the Parliament of 1397.
He was hostile in his chronicle to Richard II, was a member of the commission appointed to find secure legal grounds for his deposition, and met with the King during his captivity in the Tower of London.
Adam was rewarded for his part in Richard II's surrender, imprisonment and fall by being granted the living of Kemsing and Seal, and later made a prebend in the church of Bangor.
However one living, his title to the prebend of Llandygwydd in Cardiganshire given under the college of Abergwili, was contested by one Walter Jakes, alias Ampney, who had obtained it by exchange in 1399.
Here he attended closely to events in Wales and England and again developed his legal work, in France and Flanders this time.
His will, also preserved, includes bequests to Llandaff Cathedral and to friaries in Newport and Cardiff as well as to individual persons bearing Welsh names.
This chronicle is his major legacy, providing contemporary detail on events in Wales, England and abroad and an insight into the life of an educated man moving through important spheres of influence at the time.
Observant of phenomena from his youth, Adam is struck by the beauty of Lake Lucerne and the quality of Beaune wine, but draws a pessimistic conclusion about the night-time behaviour of Rome's canine population.
His Latin chronicle of English history from 1377 to 1421 was edited and translated by Edward Maunde Thompson for the Royal Society of Literature, as Chronicon Adæ de Usk.