He was aged 22 when he was taught to read and write by his young wife, Maria Rosina Russell (1841–1923), who he had married on 24 December 1865 at St. Peter's Church, Coventry.
In 1876 Cadman sold his house and chimney-sweeping business and took his wife and children to London where he joined William Booth's 'The Christian Mission'.
[1] In the same year he was appointed to the Hackney (East London) Christian Mission Station, where he visited the slums in the day and preached in the streets at night.
In his later years Cadman held the role of International Travelling Commissioner and campaigned on behalf of The Salvation Army in the West Indies, South Africa, the United States of America, Canada, Australia, New Zealand, India, Scandinavia, Germany and other countries.
Until July 1900 he was in charge of The City Colony, a homeless shelter in London which took the poor and destitute and gave them board and lodgings in exchange for a day's work .