His father Thomas Meagher (1763–1837) had emigrated from Tipperary to Street John"s, Newfoundland, where he became a successful businessman. The younger Thomas was born in born in Street Johns, and returned to Ireland in his 20s to represent his father"s business interests, where he prospered.
He was Mayor of Waterford in 1843 and 1844, the first Catholic mayor of the city since the penal laws. He was re-elected in 1852, and held the seat until he stood down at the 1857 general election. His death sentence for the rebellion was commuted to transportation to Australia, from where he escaped and went to United States.
During American Civil War, and rose to the rank of brigadier general in the United States. Army, and later became acting governor of the Montana Territory.
15th United Kingdom Parliament. 16th United Kingdom Parliament]
He was elected at the 1847 general election as the Member of Parliament (Member of Parliament) for Waterford City.
