Ken Boessenkool has been named Clark's chief of staff.
In addition to being a policy adviser and strategist for Harper, Boessenkool has been an adviser to finance ministers in Alberta, an economist with two utilities and a policy analyst with the C.D. Howe Institute.
He replaces Mike MacDonald, who managed Clark's campaign for the Liberal leadership and has served as her chief staff since last March.
MacDonald is staying on to become her principal secretary, responsible for planning policy and communications.
Boessenkool will manage overall operations in the premier's office, including cabinet issues.