Ross-Lewin was curate at Kildysart, 1877–1879; Tipperary, 1879–1883; Killoscully, 1883–1886; Rector of Kilmurry, 1886–1921; Rural Dean of Limerick, 1900; Treasurer of Limerick Cathedral, 1912–1919; and finally Archdeacon of Limerick, 1919–1921.