Harriet Tubman — former slave, abolitionist, “conductor” on the Underground Railroad — will not become the face of the $20 bill until after President Trump leaves office, Treasury Secretary Steven Mnuchin said Wednesday.

Plans to unveil the Tubman bill in 2020, an Obama administration initiative, would be postponed until at least 2026, Mr. Mnuchin said, and the bill itself would not likely be in circulation until 2028.

Until then, bills with former President Andrew Jackson’s face will continue to pour out of A.T.M.s and fill Americans’ wallets.

Mr. Mnuchin, concerned that the president might create an uproar by canceling the new bill altogether, was eager to delay its redesign until Mr. Trump was out of office, some senior Treasury Department officials have said. As a presidential candidate in 2016, Mr. Trump criticized the Obama administration’s plans for the bill.

That April, Mr. Trump called the change “pure political correctness” and suggested that Tubman, whom he praised, could be added to a far less common denomination, like the $2 bill. “Andrew Jackson had a great history, and I think it’s very rough when you take somebody off the bill,” Mr. Trump said at the time.