Trump, who commuted Johnson's sentence in 2018 after she had served more than 20 years in prison, signed the pardon during a meeting with Johnson in the Oval Office.
"We're taking Alice Johnson from a commutation to a full pardon," Trump said. "Alice has done an incredible job since she's been out, recommending other people" who may deserve clemency or a pardon.
Johnson, who spoke at the Republican National Convention this week about her initial commutation, wiped away tears after Trump's announcement.
Kardashian West personally lobbied Trump about Johnson's case.