President Donald Trump has picked former Reagan economist and longtime CNBC commentator Larry Kudlow as his chief economic adviser and director of the National Economic Council.

Kudlow will fill the role vacated by former Goldman Sachs executive Gary Cohn, who left the White House after differing with the president over tariffs to protect America’s steel and aluminum industries.

“Larry Kudlow was offered, and accepted, the position of Assistant to the President for Economic Policy and Director of the National Economic Council,” Sarah Huckabee Sanders said in a statement.

In an interview on CNBC, Kudlow said he would be flying down to Washington, D.C. Wednesday night and reporting to work at the White House tomorrow.

The news of Kudlow’s selection was first reported by CNBC, the financial news network with which Kudlow has long been associated.

Kudlow is best known for his advocacy of tax cuts. As an informal adviser to the Trump campaign and later the White House, Kudlow helped develop some of the ideas that became the Trump tax cut plan in 2016, which many consider the crowning achievement of Trump’s first year. Last year, Kudlow and co-author Brian Domitrovic published a book lauding the tax cuts of John F. Kennedy and Ronald Reagan.

Kudlow was once an advocate of relatively open immigration but changed his mind in 2015 following terrorist attacks in San Benardino and Paris. The U.S. should “seal the borders” and end all immigration and visas until the system can be made safer, Kudlow wrote.

Kudlow criticized the president’s call for sweeping tariffs on steel and aluminum imports. But as the administration exempted Canada and Mexico from the tariffs, and said it was opening to providing further exemptions, Kudlow appeared to back away from that critical stance. For his part, Trump said Kudlow’s disagreements with tariffs were not a dealbreaker, telling reporters Tuesday that his administration welcomed “divergent opinion.”

People who have spoken to Kudlow say he is “100 percent on board” with the Trump administration’s economic struggle against Chinese domination. Kudlow has praised the administration’s attention to the issue of intellectual property theft and forced technology transfers by China and Chinese companies.

Kudlow has credited Art Laffer, the godfather of supply-side tax cuts, as being formative in his own economic views. Kudlow, in turn, became an economic guru to many Republican and conservative tax cutters, including Jack Kemp and Rush Limbaugh. In addition to serving as a member of the Reagan economics team, Kudlow worked at Bear Stearns until 1994.