John remained in Epirus as governor until the death of Andronikos III in June 1341. He then left his post and travelled with a delegation of high officials to meet with Kantakouzenos at Didymoteichon. With the outbreak of the civil war in early autumn, he sided with Kantakouzenos and was present at the latter's acclamation as emperor at Didymoteichon on 26 October 1341. In spring 1342, Angelos followed Kantakouzenos in his abortive campaign to Thessalonica and his subsequent flight to Serbia and the court of its ruler Stephen Dushan (r. 1331–1346).