The victory takes Murray's tally of slam titles to five, three in mixed doubles and two in men's doubles, while Hingis has won 24 across singles and doubles.
Hingis thought there might be scope to play mixed doubles in March at the Indian Wells and Miami tournaments, which are played over more than week, while Murray said that mixed was "a lot of fun".
Stephens said she met Altidore, who plays for the US national team, in fifth grade.
The 36-year-old's achievement is made all the more remarkable by the 13-year gap between her 2002 Australian Open doubles title and her next at Wimbledon in 2015.
Murray and Hingis romped through the draw at Wimbledon but things were tougher here. "So that's not an issue this time, I believe", she said.
Hingis and Chan, formed this year after Chan parted ways with her longtime partner and sister Chan Hao-Ching, have dominated the circuit since forming and the second-seeded pairing did not drop a set in their six victories. Asked during her press conference about her emotions, Keys joked that "I think drinks will help me through this tough time".
Says Keys: "She can buy me drinks, all of the drinks".
Cori "CoCo" Gauff will try to become the youngest U.S. Open girls' champion on Sunday when she faces fellow American Amanda Anisimova.
Third seeds Chan and Venus lost the first set 6-1, but then rallied to claim the second 6-4 to take the final to a super tiebreak, but the top seeds proved too strong as they edged the decider 10-8 after one hour, nine minutes to add the US Open to the title they won at Wimbledon two months ago.
She returned to the tennis tour in recent years as a coach before starting to play again. "Like, a great opportunity for me to compete with Martina".