Born in Pelton, County Durham, Hepburn began working in Fatfield Colliery at age eight, moving from there to Jarrow and Hetton Collieries. In 1830-31 he formed the Northern Union of Pitmen, known locally as ‘Hepburn’s union’, to fight for the rights of colliery workers. The union took immediate action to reduce the working day from eighteen hours to twelve, as well as to secure payment in money and not tokens for the hated ‘Tommy shops’. The strike was successful but frightened the coal owners: their response was to refuse to employ workers who were members of the union. The result was the pitman’s strike of 1832.
The strike was bitter and at times violent and ended with the pitmen being starved back to work. The success of the coal owners in crushing the strike led to them outlawing the union and blacklisting the union's leaders. Thomas Hepburn was unable to find work in any of the local pits and tried unsuccessfully to make a living selling tea at the collieries. Eventually he found work in Felling Colliery on the basis that he never involved himself in further trade union activities. He kept to his word and switched his political interest to working on behalf of the Chartist movement for radical parliamentary reform. He stopped working in the pits in 1859, aged 64 and suffering from ill health. He died five years later on December 9th 1864 at his son-in-law's home in Newcastle and was buried at St Mary’s church, Heworth.
In later years his pioneering role in fighting for the rights of pitmen was recognised and commemorated each year by leaders of the National Union of Mineworkers, other unions and supporters of the labour movement gathering at his grave on the morning of the Durham Miners Gala.