The former Chancellor of the Exchequer and current MP will take up his new role in early May.
Suceeding Sarah Sands, Osbourne will edit the paper an average of four days a week, enabling him to fulfil his other commitments, including as an MP; giving him the time to vote and contribute to Parliament after the paper has gone to print.
Osborne said: "This is such an exciting and challenging job and I'm thrilled to take it on. The Evening Standard is a great paper, testimony to the hard work of Sarah Sands and the impressive team, and to the investment of its owners. I look forward to working with, learning from and leading this team of dedicated professionals.
"Growing up as a Londoner, I've always known that the Evening Standard is an institution that plays a huge part in the life of the city and its people. Now it is a great honour that I can play a part as leader of the editorial team making the Evening Standard the definitive voice of the world's most exciting city.
"I am proud to be a Conservative MP, but as editor and leader of a team of dedicated and independent journalists, our only interest will be to give a voice to all Londoners. We will be fearless as a paper fighting for their interests. We will judge what the government, London's politicians and the political parties do against this simple test: is it good for our readers and good for London? If it is, we'll support them. If it isn't we'll be quick to say so.
"So much is now at stake about the future of our country and its capital city. I will remain in Parliament, where that future is debated. I was elected by my constituents in Tatton to serve them and I intend to fulfil that promise. I remain passionate about the Northern Powerhouse and will continue to promote that cause. Right from the first speech I gave about the North of England, I've said that London needs a successful north and the north benefits from its links to a global city like London. It's not a zero-sum game, but quite the opposite."
Evgeny Lebedev, proprietor of the Evening Standard, added: "In George, we have appointed someone of huge political achievement, and economic and cultural authority. Once he put himself forward for the position, he was the obvious choice. I am proud to have an editor of such substance, who reinforces the Evening Standard's standing and influence in London and whose political viewpoint - liberal on social issues and pragmatic on economic ones - closely matches those of many of our readers.”
As required of former ministers, Osborne is seeking the advice of the Advisory Committee on Business Appointments on his appointment.
by Lydia O'Neill