Guilfoyle, who until this week was the US ambassador to Greece, was asked to resign after The Wall Street Journal reported that she had asked a donor to pay off her $US100,000 ($145,000) American Express bill before her confirmation vote. She has denied the allegation. Trump said on Tuesday that Guilfoyle "was doing a good job", but he "didn't like what I read".
The resignation is part of a larger pattern in Trump's second term, in which the prominent figures who have departed the administration, either voluntarily or involuntarily, have overwhelmingly been women.
In the northern spring, four of Trump's eight female Cabinet-level officials resigned or were fired in just three months: Attorney-General Pam Bondi, Labor Secretary Lori Chavez-DeRemer, Homeland Security Secretary Kristi Noem and Director of National Intelligence Tulsi Gabbard. All were replaced by men.
The reporting notes that women in Trump's orbit do not seem any more inclined to controversy than the men; his male appointees have repeatedly drawn scrutiny and calls for their ouster.