Who is Robert Lighthizer?

Trump thanked Lighthizer before any other members of his administration

President Trump was full of praise for the team that worked on "phase one" of the China trade deal before signing it Wednesday and thanked U.S. Trade Representative Robert Lighthizer before any other members of his administration.

"I also want to give special thanks to our U.S. Trade Representative who has been kept very busy. He's doing a lot of deals. We'll have another big one next week," Trump said. "Robert Lighthizer, are we keeping you busy enough? Poor guy can't sleep ... Bob Lighthizer is really an outstanding guy, gets along with people. He's smart, he's sharp, he understands trade better than anybody. When I first took this, I said I've got to get the best guy, and all sides pointed to Bob."

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Lighthizer addressed the room after Trump and said the deal is the "result of two years of hard work."

"The United States and China are two great countries with two great economies but two very different economic systems," he said. "It is imperative that we develop trade and economic rules and practices that allow us both to prosper. The alternative is not acceptable for either of us."

Who is Lighthizer, the somewhat tightlipped trade guru who has been in charge of talks with Chinese officials? Trump said shortly after his inauguration in January 2017 that he would nominate Lighthizer to the post.

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Lighthizer served as deputy U.S. trade representative under President Ronald Reagan.

US Trade Rep. Robert Lighthizer speaks next to President Donald Trump, remarking on the United States, Mexico, Canada Agreement (USMCA), from the Rose Garden of the White House in Washington, D.C., on Oct. 1, 2018. (JIM WATSON/AFP via Getty Images)

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Lighthizer, who played a senior role during Bob Dole's 1996 campaign, has more recently worked on trade issues as a lawyer, representing manufacturing, agricultural and high-tech companies, according to his law firm biography. Lighthizer's bio also states he focused on "market-opening trade actions on behalf of U.S. companies seeking access to foreign markets."

Yet in 2008, he openly questioned GOP presidential nominee John McCain's commitment to free trade in a New York Times opinion article.

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"Mr. McCain may be a conservative. But his unbridled free-trade policies don't help make that case," Lighthizer wrote at the time, suggesting that free trade had long been popular among liberals.

"Moreover, many American conservatives have opposed free trade. Jesse Helms, the most outspoken conservative in the Senate for three decades, was no free trader. Neither was Alexander Hamilton, who could be considered the founder of American conservatism," he wrote.

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The Associated Press contributed to this report.