On the imposition of conscription in 1916 during First World War, he was a conscientious objector, and was imprisoned. Morison married Mabel Williamson, a teacher, in 1916; the marriage was an unhappy one and Morison rapidly separated from his wife. In 1918 he became design supervisor at the Pelican Press, which published material critical of the war. He moved on to a similar position at the Cloister Press. In 1922, he was a founder-member of the Fleuron Society dedicated to typographic matters (a fleuron being a typographic flower or ornament). He edited the society’s journal, The Fleuron, from 1925 to 1930. The quality of the publication's artwork and printing was considered exceptional. From 1923 to 1925, he was also a staff editor/writer for the Penrose Annual, a graphic arts journal.

Eleven days of weariness on board a vessel not intended for the accommodation of passengers have so exhausted my spirits, to say nothing of the other causes, with which you are already sufficiently acquainted, that it is with some difficulty I adhere to my determination of giving you my observations, as I travel through new scenes, whilst warmed with the impression they have made on me. The captain, as I mentioned to you, promised to put me on shore at Arendall*, or Gothenburg, in his way to Elsineur; but contrary winds obliged us to pass both places during the night. In the morning, however, after we had lost sight of the entrance of the 2 latter bay, the vessel was becalmed; and the captain, to oblige me, hanging out a signal for a pilot, bore down towards the shore.