Former health minister George Smitherman is now the official head of a brand new Ontario "super-ministry" covering energy and infrastructure.

He was sworn into the position Friday alongside the other members of Premier Dalton McGuinty's newest cabinet.

Smitherman's new role will put him in charge of several of the government's most important projects, as well as multi-billion dollar budgets for sectors including nuclear plant construction and public transit.

"We have a responsibility to continue to drive an energy strategy that produces a clean, affordable, reliable supply of energy," he said Friday at the swearing-in ceremony.

Known among the opposition as "Furious George" for his often antagonistic manner in the legislature, Smitherman has long been one of McGuinty's top lieutenants.

His new post is seen as something of a reward after guiding the Health Ministry for five years and serving as McGuinty's deputy premier.

"I think it's a great fit, it's a natural fit," McGuinty told The Canadian Press on Friday. "And it's an essential part of our plan to grow this economy."

He said combining the two portfolios made sense considering the government's recently-announced $26-billion plan to refurbish the province's nuclear fleet.

"It's a big job, but this guy is more than capable of taking on that responsibility."

However, members of the opposition have suggested the mega-ministry will put too much responsibility on the shoulders of one minister.

"Simply turning on the 'Furious George' technique has outlived its shelf-life," NDP leader Howard Hampton told CTV Toronto on Friday.

Smitherman is not the only change to the cabinet. Stepping into the health and long-term care portfolio is David Caplan, 43, a former smoker who has admitted to struggling with his weight.

Caplan said Friday that he is trying to ignore the criticism and focus on doing the best job he can with one of the country's largest budgets.

"My own conversations between me and my doctor are private matters, (as) they are for all of us, and they'll remain private," he said.

"I think as the premier's outlined today, he has the confidence in me based upon the track record that I showed over the course of the last 4 1/2 years and I'm going to fulfill the mandate that Premier McGuinty has set out for me."

The former health minister extended his congratulations to his successor at the ceremony, noting Caplan steps into a role once held by his mother. Elinor Caplan was the health minister under Liberal premier David Peterson from 1987-1990 when the party suffered a surprising defeat by the New Democrats.

The shuffle was prompted by former energy minister Gerry Phillips' decision to step down. Phillips remains in cabinet, but without a portfolio.

With a report by CTV Toronto and files from The Canadian Press