[1][2][3] Leaving the Examiner in 1912, Cubbon became Borough Librarian of Douglas; in this period he published A Manx Book of Poetry (1913), which was particularly aimed at young people with a view to getting them involved in the culture of the Isle of Man.

[1][2][3] Following Kermode's death in 1932 Cubbon succeeded him as director, a post he held until his retirement in 1940, when he was replaced by Basil Megaw FRSE.

[1][2][3] Said to have been passionately patriotic with regard to the Isle of Man, his appointment as Director of the Manx Museum was said to have been Cubbon's great ambition.

[1][2][3] During his time at the Manx Museum, Cubbon compiled the Bibliography of the Literature of the Isle of Man, published in two editions in 1933 and 1939; he also conducted numerous explorations for the Antiquarian Society and gave lecture on various subjects.

[1][2][3] Cubbon celebrated the centenary of the publication of Archibald Cregeen's dictionary in Peel in 1938 stating that "we students would be poor without his precious book".