He was educated at Kingston School, Yeovil.
He later on married Mrs F. I. M. Norton. In 1938 he was made a Commander of the Order of the British Empire. Rowsell was a pharmacist.
He was a Fellow of the Chemical Society.
He was Director of the South Western Board of Sun Insurance. He was Director of the North Devon and Cornwall Railway.
He was a Fellow of the Chartered Insurance Institute. He was Treasurer and Past President of the National Association of Insurance Committees.
He was Chairman of the Devon Insurance Committee from 1916-1945.
In 1914 he was selected as Liberal prospective parliamentary candidate for Somerset division of Bridgwater. However, due to the outbreak of war, the general election was postponed. During the European War he was Chairman of Recruiting and War Savings Committees.
By the time the elections took place in 1918, a Coalition government sought re-election and gave endorsement to the sitting Unionist Member of Parliament. As a result he withdrew and did not contest the 1918 elections.
He was a County Alderman and Chairman of the Finance Committee. He served as Mayor of Exeter from 1921-1924.
During his three-year term as Mayor, he made the Devon and Exeter Cancer Fund his mayoral charity and raised £11,000 to equip the new X-ray, Radium and Electrical Treatment Department at the Rural Delivery&East. He was Vice-President and Treasurer of the University College of the South West. He was President of the Exeter and Western Counties Hospital Aid Society.
He served as a Justice of the peace in Devon and Exeter.
He was Liberal candidate for the Totnes division of Devon at the 1929 General Election. The seat had been Liberal until 1924 when it was lost to the Unionists. The Unionists held onto the seat, though their majority was reduced;
He did not stand for parliament again.
In 1911 he was appointed by the Liberal government as a Member of the Central Advisory Committee for the setting up of National Health Insurance. In 1920 he was appointed a Member of the Central Profiteering Committee. He then concentrated on local government in Exeter and as a member of Devon County Council.