In 1920 he became the Society for Nautical Research's honorary secretary and treasurer, and remained so until his death. He then moved to head Dartmouth Royal Naval College's history department in 1921, but after only a year moved to be the first Professor of History at the Royal Naval College, Greenwich during the addition of a staff college and a war college to the institution. This was part of a move to incorporate study of naval history into naval education, a need for which had been shown by the recent First World War, and it was in this job that Callender wrote The Naval Side of British History (1924) and headed up the SNR's successful campaigns to save HMS Victory for the nation and to found a naval and maritime museum for the United Kingdom.