Sexton was born in Newcastle upon Tyne on 13 April 1856 to an Irish-born family of market traders, who soon moved to St Helens, Lancashire. After leaving school he worked in a variety of jobs, including as a seaman and in a chemical factory, before becoming a docker on Liverpool Docks. In 1884 he set up his own business as a coal merchant.
Sexton was born in Newcastle upon Tyne on 13 April 1856 to an Irish-born family of market traders, who soon moved to St Helens, Lancashire. After leaving school he worked in a variety of jobs, including as a seaman and in a chemical factory, before becoming a docker on Liverpool Docks. In 1884 he set up his own business as a coal merchant.