[1] Donnelly was among the group of Volunteers that assembled for the Easter Rising of 1916 in Coalisland, County Tyrone.
[3] In 1921 he joined Éamon de Valera's anti-treaty forces and worked to end partition until his death.
In February 1923 Donnelly was interned by the Irish Free State military and released in August.
[1] During the 1920s Donnelly worked with the Anti Partitionist Cahir Healy to establish a unified approach against partition.
[7] In 1942, Donnelly was again elected to the Parliament of Northern Ireland, this time in a by-election for Belfast Falls.