He was born at Shediac, New Brunswick, the son of Daniel Hanington, and was educated there and at Mount Allison Academy in Sackville.
Hanington ran unsuccessfully for a seat in the provincial legislature for Westmorland in 1870 but was elected in an 1870 by-election as a Liberal-Conservative.
Hanington was sympathetic to Acadian rights and appointed a member of that community, Pierre-Amand Landry, to the senior cabinet position of provincial secretary.
However, Hanington faced a leader of the opposition, Andrew G. Blair who had organised the Liberal Party into a powerful force.
In 1883, Blair defeated Hanington's Conservative government in a Motion of No Confidence and won the subsequent election.