Television commentator Lawrence Kudlow has accepted the role of top economic adviser to US president Donald Trump, the White House confirmed.
Mr Kudlow will lead the National Economic Council after Gary Cohn quit last week.
Mr Cohn resigned after disagreeing with Mr Trump about his planned tariffs on metal imports.
Mr Kudlow, a former Bear Stearns investment banker, is currently a pundit on business news channel CNBC.
Critics have pointed out his awry predictions in recent years, including that "the outlook for stocks is getting better and better" in September 2008. Days later the stock market crashed amid the global financial crisis.
"Larry Kudlow was offered, and accepted, the position of Assistant to the President for Economic Policy and Director of the National Economic Council," White House spokeswoman Sarah Sanders said.
"We will work to have an orderly transition and will keep everyone posted on the timing of him officially assuming the role."
Larry Kudlow will be my Chief Economic Advisor as Director of the National Economic Council. Our Country will have many years of Great Economic & Financial Success, with low taxes, unparalleled innovation, fair trade and an ever expanding labor force leading the way! #MAGA— Donald J. Trump (@realDonaldTrump) March 15, 2018
Mr Kudlow confirmed the news to Reuters news agency earlier.
He was an early supporter of Mr Trump, and is a well-known conservative voice.
What is his background?
He was born in New Jersey and studied at the University of Rochester and Princeton's school of public and international affairs.
His career in economics started with a junior position at the New York branch of the Federal Reserve.
He moved to work as an economist for Wall Street firms and for former President Ronald Reagan in Washington, where he helped to make the case for the first round of 1980s tax cuts.
In 1994, Mr Kudlow spoke to the New York Times about battling drug and alcohol addiction, saying he hoped his story would help others in the position. The problem had led to his resignation as chief economist from the Bear Stearns investment bank.
Mr Kudlow, who calls himself a "long-run optimist", subsequently re-invented himself as a media personality, hosting radio and television programmes, including for the business news channel CNBC, where he remains a contributor.
Analysis: BBC US business reporter Joe Miller
In his trademark blue pinstripe shirts and monogrammed cufflinks, Larry Kudlow has been a fixture on US financial television for more than a decade, and a reliable cheerleader for American business.
A proponent of lower taxes, Mr Kudlow made his name at the ill-fated Bear Stearns before working in the Reagan administration.
He denounced Donald Trump's comments about women in a tape released during the 2016 presidential campaign, and has repeatedly criticised the White House for its attacks on free trade - including the recently announced tariffs.
But the president, who once worked as a Wall St pundit alongside Mr Kudlow, was reportedly won over by his TV presentation skills.
Where does he stand on the issues?
Mr Kudlow is known as a "supply side" economist - a champion of lower taxes, which he says spur consumer spending and lead to economic growth. He was an informal adviser to Mr Trump during the presidential campaign.
He is also a self-described "inflation hawk" - though he has called recent concerns "misplaced".
As an ardent free-trader, he has defended the North American Free Trade Agreement and was critical of President Trump's recent plan to impose 25% tariffs on foreign steel and 10% tariffs on foreign aluminium.
But he praised the president for exempting Mexico and Canada. He has also urged targeted action against China, especially when it comes to intellectual property.
Those views make him a fairly typical, establishment Republican - which makes it a bit of a surprise that Mr Kudlow is a former Democrat and was a member of the left-wing Students for a Democratic Society.
What is the reaction?
FreedomWorks, a conservative group that advocates for lower taxes, had urged Mr Trump to select Mr Kudlow,
Others have been more sceptical.
David Stockman, Mr Kudlow's former boss during the Reagan administration, told the Washington Post in 2016 that Mr Kudlow's prediction that tax cuts would lead to growth was "dead wrong". Instead, he said the cuts led to budget deficits.
More recently, he has warned that Mr Kudlow would not be able to rein in the president.
"As much as I love him ... Larry's voice is exactly the wrong voice that Donald Trump ought to be hearing as we go forward," he told CNBC.
Liberal economist and New York Times columnist Paul Krugman has been sharply critical, noting that Mr Kudlow missed signs of the housing bubble and recession.
"At least he's reliable -- that is, he's reliably wrong about everything," Mr Krugman tweeted.
Indeed in December 2007 - just as the recession was beginning - Mr Kudlow wrote in the National Review: "There's no recession coming. The pessimistas were wrong. It's not going to happen."