He loses the less demanding portfolio of Consumer Affairs, which he has held since March last year when he became a minister outside Cabinet.
Mr Bridges was thrilled at his elevation to the inner sanctum. "It is the real decision-making centre for Government. To sit around the table with the PM and other members is a great privilege."
He made no secret of the fact he was ambitious. "The higher you go, the more difference a person can make."
However, he insisted he was taking things one step at a time and admitted to the "possibility" of climbing higher in Cabinet than his ranking of 19th out of 20.
Asked whether one day he could become Tauranga's first prime minister, he responded: "I am just chuffed to have these responsibilities. I don't want to get ahead of myself. At the moment I am wanting to live up to the confidence that the prime minister has placed in me."
Mr Bridges learned of his promotion from Mr Key yesterday morning, before the public announcement of the reshuffle.
"He gave me the good news and congratulated me. He told me I had done a really good job in my first year as minister and I thanked him for the faith he put in me."
His appointment to the Energy and Resources portfolio comes at the expense of Phil Heatley.
Asked if he had lobbied for any of his new postings, Mr Bridges replied "not really". He said he had expressed interest in the Labour portfolio which had been under the caretakership of Chris Finlayson.
His new responsibilities meant Mr Bridges would have to "pack his sandwiches" for Wellington on Monday rather than Tuesday and not return until Thursday night.
"Our weekends will be the more important," he said of the impact his new responsibilities would have on his family life with wife Natalie and their 10-month-old son Emlyn.
The family has recently shifted from Mount Maunganui to a new home in Matua.
"Natalie is very excited for me. She knows it is a real step up," Mr Brides said.
Asked how being a member of Cabinet would impact on his job as MP for Tauranga, Mr Bridges said: "If anything it enables me to do a better job for the city because I will have more power to effect change.
"My new responsibilities in Wellington will see me serving Tauranga very effectively."
He has also shed the job of Associate Minister of Transport although he remains the Associate Minister for Climate Change Issues.