Former chancellor George Osborne says he is quitting the House of Commons "for now".
The Conservative MP for Tatton said he was "very excited" about becoming the new editor of London's Evening Standard newspaper.
He told his local Tory party he would be using the role to provide "straight facts and informed opinion" through the paper's general election coverage.
MPs have backed Theresa May's call for a snap election on 8 June.
Mr Osborne told the BBC's John Pienaar he would be fighting for the same values he had as chancellor and an MP of 16 years standing.
But as Evening Standard editor he would also "speak for London, speak for my readers and speak for this country and its future".
"Our country has got some big decisions to make now about the kind of Britain we want to be and those values of openness, tolerance and enterprise are ones I hold dear," he said.
Asked if he believed Mrs May understood the concerns of people who voted for Britain to remain in the EU, he said: "We have got to make sure that not just London's voice is heard, but the voice of a Britain that wants to play a big role on the world stage, that celebrates the fact we have a diverse society, that is optimistic about the future, not afraid about the future - those are things I have always believed in."
Earlier, in a letter confirming he would not be seeking re-election, Mr Osborne said: "It's still too early to be writing my memoirs."
At the age of 45, he did not to spend the rest of his life "just being an ex-chancellor", he said. "I want new challenges. I'm very excited about the opportunity to edit the Evening Standard."
He added: "More so than at any time in my life, the public need from the media the straight facts and informed opinion to help them to make the big decisions Britain now faces about the country we want to be.
"That starts with the coverage of this general election."
Following last month's announcement that Mr Osborne would be taking over as editor of the London-based free newspaper from Sarah Sands, questions had been asked about how he would combine that role with being an MP for a northern constituency.
Labour leader Jeremy Corbyn described the appointment as a "joke" and called for an immediate by-election in Tatton.
"The appointment makes a mockery of the independence of the media," he said at the time. "It takes multi-tasking to a new level and is an insult to the electors he is supposed to serve."
But Mr Osborne defended himself, adding that he believed having MPs who could draw on outside experiences was good for Parliament as it enabled former ministers, in particular, to "continuing to contribute to the decisions we make".
Mr Osborne, who was chancellor for six years, had ambitions to be a journalist as a young man.
He failed to get a place on The Times' trainee scheme after graduating from Oxford University - at which he edited its Isis magazine - and was briefly a freelance reporter on the Daily Telegraph's diary column.
Since being axed as chancellor by Theresa May when she became PM last July, Mr Osborne has picked up a number of other jobs.
George Osborne's various jobs
- MP for Tatton: Paid £74,962 a year
- Editor, London Evening Standard: Paid £200,000, according to reports
- Adviser, BlackRock Investment Institute: Paid £650,000 a year
- Chair, Northern Powerhouse Partnership: Unpaid
- Kissinger Fellow at the McCain Institute: £120,212 stipend to cover travel and research costs
- Washington Speaker's Bureau: Paid nearly £800,000 for engagements since July