In announcing his decision to withdraw the nomination of Jared Isaacman, a billionaire entrepreneur, to run NASA on Saturday, President Trump cited a review of his “prior associations,” a veiled reference to donations Mr. Isaacman had made to Democrats.

But those donations were old news. While Mr. Trump privately told advisers in recent days that he was surprised to learn of Mr. Isaacman’s contributions and that he had not been told of them previously, he and his team were briefed about them during the presidential transition in late 2024, before Mr. Isaacman’s nomination, according to two people with knowledge of the events.

One of those people said Mr. Isaacman, who had already been approved by a Senate committee and was headed to a confirmation vote this week, directly told Mr. Trump about those donations when they met in person weeks after the 2024 election.

A White House spokesman did not immediately respond to requests for comment. Reached by phone, Mr. Isaacman declined to comment.

The revelation came after Mr. Trump told associates that he had recently been informed of Mr. Isaacman’s donations to prominent Democrats, including in the past two campaign cycles.

Mr. Isaacman is the founder of a payment processing company and a close associate of Elon Musk, who after the election personally lobbied for Mr. Isaacman to get the NASA job. Mr. Isaacman has flown to space twice with Mr. Musk’s company SpaceX, which has several contracts with the space agency.