He joined the monastic community founded by his father at Meteora, where he is documented under his monastic name Joasaph in 1381. Although he had surrendered political power, John Uroš remained wealthy and influential. In 1384–1385 he helped his sister Maria govern Epirus after the murder of her husband Thomas II Preljubović. He endowed the monasteries at Meteora and eventually became the head of the local monastic community, rebuilding or establishing further monasteries in the area in 1388 and 1390. In the 1390s he visited Mount Athos, but was back in Meteora by 1401, and died there in 1422 or 1423.