Ambani, who became the first Indian woman to join the IOC when she was elected to the prestigious body on August 4, gave away the gold medal to world record-holder American Kathleen Ledecky, silver to Jazz Carlin of Great Britain and bronze to another American Leah Smith.
Ledecky won the event in a world record timing of 3 minutes 56.46 seconds, while Carlin and Smith came second and third in 4:01.23 and 4:01.92 respectively.
Former Indian Olympic Association Secretary General, Randhir Singh, who served as IOC member from India from 2001-2014, is currently an honorary member of the global body which governs Olympic sports in the world.