Hugh Segal says he is going to become master of the University of Toronto's Massey College.
Segal was at odds with his party this fall over its decision to push through legislation suspending three senators at the heart of the ongoing expense scandal without pay.
There has been speculation he would depart, though in a statement released Thursday he praised Prime Minister Stephen Harper for his "support and counsel" during his time in the Senate.
Segal was appointed to the Senate in 2005 by Liberal Prime Minister Paul Martin, but had a long career as a backroom power in federal and Ontario politics.
Segal served as chief of staff to Brian Mulroney and there was an effort in 1993 to draft him to run in the leadership race to succeed the prime minister.
In 1998 Segal did seek the leadership of the then Progressive Conservative party and finished second to Joe Clark.
Segal also held a senior position in the government of former Ontario premier Bill Davis.
"As a proponent of senate reform I have spoken in favour of term limits as a feasible start to this process," Segal said in a statement issued Thursday night.
"Late 2014 would mark my ninth year in the senate and the time is right for new challenges."
The current master of Massey, John Fraser, issued a statement calling Segal a "warm, engaging and energetic figure."
Segal is the third Conservative senator to quit in recent weeks _ Ontario Sen. David Braley announced earlier this month he is quitting while Nova Scotia Sen. Gerald Comeau said last month he is stepping down.
Segal's departure will not affect the Harper government's commanding majority in the upper chamber, where it currently holds 57 seats compared to 32 for the Liberals.
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