Peter Navarro, a trade adviser to former President Donald J. Trump, entered federal prison in Miami on Tuesday. He is the first senior Trump administration official to serve time for his involvement in attempting to overturn the results of the 2020 election.

Mr. Navarro, 74, who played a role in Mr. Trump’s efforts to remain in power after losing the election, was sentenced to four months in prison in January for contempt of Congress. This was due to defying a subpoena from the House select committee investigating the Jan. 6 riot.

Before checking into the Federal Correctional Institution in Miami, Mr. Navarro held a press conference in a parking lot near a shopping center, blaming the Justice Department, the Biden administration, the federal trial judge, and various politicians for his situation.

He expressed concern for the future impact of his sentence on all Americans, regardless of their political affiliations.

Despite continuing to appeal his conviction, Mr. Navarro is likely to serve his full sentence. He aims to work as a law library clerk or in another low-intensity role while in prison.

Known for his unique persona, Mr. Navarro’s imprisonment marks the end of a legal battle that reached the Supreme Court.

Mr. Navarro, a Harvard-trained economist, strongly criticized China and influenced Mr. Trump’s trade policies. He had a varied career, including stints in academia and involvement in politics.

His conviction sets him apart from other Trump allies who faced legal issues but avoided severe consequences.

The imprisonment of Mr. Navarro is part of a larger legal battle involving Trump associates and their actions related to the 2020 election. While some faced minimal consequences, others like Mr. Navarro now serve time for their involvement.