Labour's Andy Burnham vowed to get the voice of the north of England to be "heard more loudly than before" as he became the first mayor of the Greater Manchester Region on Friday 5 May.
The Merseyside-born former minister, 47, was elected in the first round on 63% of the vote. Burnham, who had been an MP for Leigh for around 16 years, attacked Westminster for leaving people behind.
"They have created this crisis in politics which we are living through now," he said.
"Greater Manchester is going to take control, we are going to change politics and make it work for people. We will get the voice of the north be heard more loudly than before."
The role will see Burnham oversee a combined authority, including Oldham, Stockport, Tameside, Rochdale, Salford, Trafford and Wigan.
He will have powers over transport, economic development, housing and health across the North West region.
Fellow Labour politician Steve Rotheram, a former parliamentary aide to left-wing leader Jeremy Corbyn, had already been elected mayor for the nearby Liverpool City Region.
"The vast majority of people in our area have also sent a very clear message to Theresa May," Rotheram said. "Prime minister, you may use Labour's language about a country that works for all, but how can it if you hit areas like ours with the hardest of cuts?
"You claim to be the party of working people and social justice. There's only one party for social justice and that's the Labour Party."
But the local and metro mayoral elections produce bad results for Labour, with scores of council seats being lost across England and Wales as well as the Tees Valley mayor race going to the Tories.
The results come just five weeks before the general elections on 8 June. The latest opinion poll from YouGov, of more than 2,000 people between 2 and 3 May, gave the Tories a 19 point lead over Labour (48% versus 29%).