The turnaround comes just weeks before Hunter Biden's sentence was to be announced. The president's son risked imprisonment after being convicted in one court case and admitting guilt in another.
Joe Biden has on several occasions ruled out a pardon for his son and said that he would "respect the legal process".
Despite this, the president announced during the night to Monday, Swedish time, that he had issued an official pardon for Hunter Biden.
Biden: "Judicial error"
"No reasonable person looking at the facts in Hunter's case can come to any other conclusion than that Hunter was targeted just because he is my son – and that is wrong", says the president in a statement, calling it a "judicial error".
Hunter Biden, 54, was convicted in June for illegal possession of firearms after lying about his drug use when applying for a gun license. He had addiction problems when the crimes were committed.
Additionally, he admitted guilt in September to tax crimes during the years 2016-2019 – just hours before the trial was to begin. According to Biden himself, he admitted guilt to spare his family another trial and the intrusion into their private lives it would entail.
"Has taken responsibility"
For the tax crime, Hunter Biden risked up to 17 years in prison, and the firearms offense is punishable by up to 25 years. But likely, the sentence, if he had not been pardoned, would have been shorter in practice.
The pardon, however, applies not only to these crimes – but to all other "crimes in the USA that he has committed or may have committed or participated in during the period from January 1, 2014 to December 1, 2024".
Hunter Biden announces in a written statement that he will never take the mercy shown to him for granted, and promises to dedicate his life to "helping those who are still sick and suffering".
"I have admitted and taken responsibility for my mistakes during the darkest days of my addiction – mistakes that have been exploited to publicly humiliate and shame me and my family for political points", says Hunter Biden.
Joe Biden says that he made the decision over the weekend, when the Thanksgiving holiday was celebrated in the USA. The president celebrated together with his son and his family in Nantucket, Massachusetts.
"I hope that the American people will understand why a father and a president would come to this decision", says Joe Biden.
Hunter Biden, born 1970, is a businessman and lawyer with a degree from the prestigious Yale University. He is the son of the current US President Joe Biden and his first wife Neilia Hunter.
In 1972, his mother and one-year-old sister died in a car accident. Hunter and his older brother Beau were in the car and were injured but survived.
In 1977, Joe Biden remarried to educator Jill Tracy Jacobs. In 1981, they had daughter Ashley Biden.
In 2015, the family was struck by another tragedy when Joe Biden's eldest son Beau died of brain cancer.
Hunter Biden has struggled with alcohol and drug addiction for much of his life. His business dealings in Ukraine, particularly his cooperation with the energy company Burisma, have been the subject of several investigations.