Mnuchin exchanged vows with Scottish actress Louise Linton in a fairytale ceremony at Andrew Mellon Auditorium, with Vice President Mike Pence officiating the service.
Linton, originally from Edinburgh, whose credits include a supporting appearance in Lifetime's made-for-tv movie William & Kate, chose a princess-style gown custom designed by Ines Di Santo for the big day; but with an estimated net worth of $300 million, money is no object for the former Goldman Sachs banker and his new wife.
The pair first met four years ago while attending a wedding in Los Angeles and he proposed two years later, according to the New York Times.
It is the third marriage for Mnuchin, who divorced his second wife Heather in 2014 after 15 years of marriage. It is the second for Linton,
Pink was clearly the theme of the night as Melania opted for a baby pink silk chiffon gown by Gilles Mendel with Manolo Blahnik pumps, while her stepdaughter Ivanka wore a similar shade as she attended the bash with husband Jared Kushner, dressed in a classic black tuxedo.
White House press secretary Sean Spicer and his wife Rebecca Miller were also in attendance.
The bride said she admired an oval ring in the window of a Miami jewellery store early on in their relationship and she was thrilled when he popped the question with a similar piece in 2016.
"We were at Art Basel in Miami a few years ago and we walked past a jewelry store. We stopped to admire the shape of an oval engagement ring in the window. It’s quite an old-fashioned shape but I love it. Three years later he proposed to me with an oval ring just like the one we saw in the window," she told Town & Country magazine.