The federal misdemeanor charges against Hunter Biden arose from an investigation by David Weiss, the U.S. attorney in the Democratic president's home state of Delaware - who was appointed by Republican former President Donald Trump.
Along with the guilty plea on the tax charges, according to the federal plea deal, Hunter Biden also entered the pretrial diversion agreement on one firearm offense.
Biden, 53, for years has been the focus of unrelenting attacks by Trump and his Republican allies who have accused him of wrongdoing relating to Ukraine and China, among other matters.
Hunter Biden has worked as a lobbyist, lawyer, investment banker and artist, and has publicly detailed his struggles with substance abuse.
Hunter Biden disclosed in December 2020 that Weiss's office was investigating his tax affairs. He denied wrongdoing.
Hunter Biden described in a 2021 memoir dealing with substance abuse issues in his life including crack cocaine use and alcoholism. He was discharged from the U.S. Navy reserve in 2014 after testing positive for cocaine, sources said at the time.
The Weiss inquiry initially examined potential violations of tax and money laundering laws in foreign business dealings, principally in China, sources told Reuters. The investigation headed by Weiss began as early as 2018, according to U.S. media reports.
The president has two surviving children, Hunter Biden and daughter Ashley Biden. His son Beau Biden died in 2015 of cancer and his daughter Naomi Biden died as an infant after a car accident that also killed Joe Biden's first wife.
Hunter Biden appears to be the first child of a sitting president to be indicted, according to Aaron Crawford, who specializes in presidential history at the University of Tennessee.
Crawford said the family of several presidents were ensnared in scandals, including George H.W. Bush's son Neil, who directed a failed savings and loan, and Richard Nixon's brother Don, who was rescued from business failures by wealthy businessman Howard Hughes.