Pete Buttigieg, the mayor of South Bend, Indiana, who is exploring a White House run, gave an interview to Fox News Sunday, a potentially ideologically incongruous step for a 37-year-old Democrat who likes to joke he appeals to “white Episcopalian gay veteran” voters.

“I think everyone wants to fit you on an ideological spectrum which I think has never been less relevant,” he said, when asked about the ideological sweep of the Democratic field, from centrists like Beto O’Rourke to leftwing progressives such as Bernie Sanders.

“More and more people want to know what your ideas are and whether they make any sense.”

Buttigieg said he had succeeded as mayor of South Bend, where he has been in office since 2012, by governing in accordance with progressive values but earning support from Republicans and independents through not “trying to manage exactly where I was on the left-right spectrum but by trying to do the right thing”.

“I view myself as a progressive but these labels are becoming less and less useful,” he said.

The US navy veteran said he established his exploratory committee in January as a way to gauge responses “to the idea of a midwestern millennial mayor entering the conversation for president”, and to see if anybody would take note in early voting states and how fundraising might go.

“We’re seeing all of those things,” he said, “but because I’m not highly famous or personally wealthy it takes a little bit to put all the organisation in place.”

Buttigieg made an impressive presidential town hall debut last weekend, telling an audience convened by CNN he questioned how Vice-President Mike Pence, like him a Christian from Indiana, could work in a “porn star presidency” with Donald Trump, with whom the adult film star Stormy Daniels claims to have had a sexual liaison.

Since then he has emailed supporters to say he has met a qualifying threshold for this summer’s Democratic debates, by receiving contributions from more than 65,000 individual donors.

On Fox News Sunday, he said “all the signs are pointing in the right direction” for a White House run.

“You only get to launch once and I can tell you it’s going to be a big one,” he said.

If successful, Buttigieg would not only become the first openly gay president and the youngest president in history, he would also be the first to ascend directly to the White House from being mayor of a city of any size, let alone one with a population of just 102,000.

Asked about O’Rourke, a 46-year-old former US representative from Texas who narrowly lost a Senate race last year, Buttigieg contested the idea of preordained political purpose.

O’Rourke told Vanity Fair this week he felt he was “just born to be in” the presidential race.

“I think I was born to make myself useful,” Buttigieg said.

He also deflected questions about other Democratic candidates, saying he was “not combating anybody, they’re going to be competitors rather than opponents”.

But he did emphasise his youth, saying: “I do believe I’m not like the others. I belong to a different generation. I was in high school when school shootings started to be the norm, we’re the generation that’s going to be on the business end of climate change and also the generation that’s on track to make less than our parents if nothing is done to change the direction of our economy.”

Asked to identify his core policy ideas, he said his candidacy would be about generational change and would focus on “liberty, democracy and security”. He also said the Green New Deal, as championed by progressives in the Democratic party and ridiculed and attacked on the right, was more of a goal than plan.

“It’s a handful of pages laying out a goal for us to cut carbon emissions before they destroy our economy and any prospect for people in my generation to do well,” he said. “If we don’t act aggressively and immediately on climate its not going to be a pretty picture.”

The timetable for action, he added, would not be set by Congress “but by reality and science”.

What advocates of the Green New Deal get right, he added, “is that it recognises there’s also a lot of economic opportunity in this”.

Buttigieg was also asked about his roots in the industrial midwest, an area where Democrats are perceived to have lost touch with voters who went for Trump. He said he would offer a combination of attributes, including his military service as an intelligence analyst in Afghanistan, that was simply different from other candidates.

“I’m looking forward to competing,” he said. “I know I’m the young face in this conversation but not only do I have more years of government experience than the president, I have more years of executive experience than the vice-president.”