He and his brother James were educated at the Presentation College, Grand Parade, Cork; together they then visited Denmark, where they studied butter manufacture.
[1] After a short time Thomas took charge of the substantial Irish business, and on the death of their uncle the two Dowdall brothers and their cousin J.
They soon built up an extensive butter business in Cork, with branches in Manchester, London, and Cardiff; the company also manufactured margarine and soap.
[1] Dowdall was a keen supporter of the Irish Volunteers and later of Sinn Féin; he endorsed the 1921 Anglo-Irish Treaty and used his influence with others to have it ratified.
[3] Dowdall rarely spoke in the Dáil, but he was a strong advocate of re-afforestation, and outside the chamber he was a co-founder of the Forestry Society and contributed towards the publication of John Mackay's The rape of Ireland (1940).