He spoke in the context of a procedure with fragile foundations.
Joe Biden's brother was heard Wednesday by Republican elected officials in Congress who are leading an impeachment investigation against the president, accused of having lied to the American people about his family's affairs.
This investigation is brushed aside by the Democrats, who see it as political maneuvering in the middle of an election year.
It has almost no chance of succeeding.
Republicans have questioned James Biden, 74, over a series of financial transactions that they say incriminate his brother, the Democratic president.
“I have been doing business for 50 years (…) Joe Biden has never been involved and has never had any direct or indirect financial interest in these activities.
None,” James Biden declared before this committee, according to comments reported by several media.
The right accuses Joe Biden, so far without conclusive proof, of having used his influence when he was vice-president of Barack Obama (2009-2017) to allow his family to conduct questionable business in Ukraine and China .
At the heart of the investigation, Joe Biden's brother and the president's son, Hunter.
Informant prosecuted for false accusations
But the Republicans' investigation was weakened by the indictment in mid-February of a former FBI informant, Alexander Smirnov, prosecuted for having lied and fabricated false accusations of corruption against Joe Biden's son.
This 43-year-old man had accused Joe and Hunter Biden of having each received five million dollars in bribes to allow a Ukrainian gas company, Burisma, to escape prosecution.
A fabricated story, according to the indictment.
Read alsoAmerican primaries: Joe Biden, an octogenarian in the campaign
On Tuesday, US prosecutors reported that Alexander Smirnov admitted to receiving some of his information from people linked to Russian intelligence.
A businessman now converted to painting, Hunter Biden is a favorite target of Republicans, who fuel suspicions about his business affairs.
But the ongoing judicial investigation into the president's son has so far failed to substantiate these accusations.
It especially highlighted his problems with addiction to drugs and alcohol - which he claims to have overcome - and led to two indictments against him: one for tax evasion, and the other for illegal detention of firearm.