Robert K. Hur will walk into a Capitol Hill hearing room on Tuesday as a uniquely unifying figure in divided Washington — a man disdained by Democrats and Republicans alike.

In February, Mr. Hur, the special counsel who investigated President Biden, concluded a yearlong investigation into Mr. Biden’s retention of sensitive government documents by finding that the president should face no criminal charges.

But Mr. Hur, using language Mr. Biden’s team saw as gratuitous, politically damaging and outside his job description, described the octogenarian president as “a sympathetic, well-meaning, elderly man with a poor memory,” likely to be acquitted by any jury.

Mr. Hur, 51, will face withering questioning from both parties when he testifies before the House Judiciary Committee to explain his exoneration of Mr. Biden and the barbed prose in his 345-page report.

Republicans are likely to pepper him about his interactions with Justice Department officials and his legal justifications for not charging Mr. Biden, despite finding evidence suggesting that he knew some of the material he possessed was secret. Democrats will almost certainly slam him for making broad assertions about Mr. Biden’s memory and try to undermine his authority to make such an assessment.

“Nobody ever said this was going to be easy,” said Rod J. Rosenstein, a former deputy attorney general, who tapped Mr. Hur as his top aide during a tumultuous period that included the appointment of the special counsel Robert S. Mueller III to investigate his boss at the time, President Donald J. Trump.