Described as “a clever and attractive girl with a tremendous power for making friends”, she was 19 when she joined Inghinidhe na hEireann (Daughters of Ireland). In 1909 she helped found Na Fianna and became an actress at The Abbey.
With experience of editing the feminist paper Bean na HEireann she got a secretarial job with James Connolly. Helena soon became a member of the Irish Citizen Army and in 1915 became the Secretary of Irish Women Workers’ Union. Through the office of the Union, at 29 Eden Quay, knew the men who would form the Military Council which planned the Rising.
Molony was assigned to the ICA City Hall garrison for the insurrection, but they failed to take Dublin Castle. After the surrender she was imprisoned in England but released on Christmas Eve, 1916. Still active in politics, she was a member of Sinn Féin, a courier for Michael Collins and Liam Mellows during the War of Independence, and active in Civil War during which she opposed the new Irish Free State government.
In later years she was a member of the Trades and Labour Council and occupied a position of trust in the labour movement up until the 1960s. She later became a leading trade unionist and continued to fight for the rights of women workers.