Calvert, who led the province from 2001 until 2007, told a crowd gathered for the event in the rotunda of the legislature that just days after being sworn in as premier, he was contacted by the chief of protocol about having the portrait done.
Calvert said he was leading a minority government, trying to assemble a cabinet, dealing with a drought and looking at oil worth $20 a barrel.
"Somewhere on the extremities of my mind was the question of picking a portrait artist," Calvert recalled.
But the chief of protocol, Michael Jackson, persisted. Memos on the issue kept coming and gained urgency.
"I actually phoned Michael and said to him 'Michael, just what's the panic about this portrait?' " said the one-time New Democrat leader.
"He said to me, 'Do you want the truth?' I said 'Well, yeah the truth is helpful.' He said to me 'Well the truth of matter is this: we paint you early because you guys age so fast in the job.' "
"Now, I'm not sure, Mr. Premier, if you've had the same advice," laughed Calvert, turning to current Saskatchewan Premier Brad Wall, "but it wasn't all that encouraging right at the start."
Wall called Calvert a statesman and gentleman.
"You, sir, possess a very rare mix of qualities I believe are required to mark a successful public life," Wall said.
"You're a gifted public speaker. You're a skilled debater, not afraid to mix it up, but to do so with reasoned arguments, with humility and with a sense of humour."
The portrait by Susanne MacKay Kaplan shows a smiling Calvert standing outside with the west wing of the legislature in the background. It was immediately displayed in the Saskatchewan Gallery, where portraits of all former premiers hang.
It is the first official portrait to show a premier outside the legislature.
Calvert said that's by design.
"It was in the community of Saskatchewan that I found the greatest rewards of serving in this office," he said.
"And it was my conviction and remains my conviction that all that happens within this building is only of importance as it touches the lives of those apart from this building. What matters is not so much what happens in here, but how what happens in here can better build a province."