John Patrick Campbell (1883–1962) was a Belfast-born artist known for his illustrations in publications by members of the Gaelic League published under the name Seaghan MacCathmhaoil.

John Campbell was born in Belfast on 7 March 1883 one of ten children of William and Catherine.

[2] Their family were Catholic and Nationalist, and their father a Parnellite, whilst their mother was of a Presbyterian background.

[3] His skill was recognised early on and in 1904 whilst still at the School of Art sent one of his works to the 1904 St. Louis World's Fair.

[6] He also illustrated his brother Joseph Campbell's folk poetry, in The Rushlight, under the pseudonym 'Ceann-Maor' (Big Head).