Notley says Mason will provide wisdom, leadership and guidance in the assembly.
She says Mason will reach out to opposition caucus house leaders in the coming days to talk about the upcoming session.
Mason says he's honoured to receive the appointment and looks forward to working with all members of the legislature.
He was first elected to the legislature in Edmonton Highlands-Norwood in a 2000 byelection.
Notley said the legislature will be recalled on June 11 to elect a Speaker, and the speech from the throne to be delivered on June 15.
The new premier and her cabinet will be sworn in Sunday at the legislature.
"I'm very honoured to have received this appointment from our incoming premier," Mason said in a news release.
"I look forward to working together with our new caucus. I'm also looking forward to working with opposition members of the legislature in the days ahead, demonstrating that we can disagree without being disagreeable."
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