Harkness took up dancing and ice skating to lose weight and was highly disciplined in both endeavors.

Harkness was friends with a young Potter Stewart, whom she affectionately called "Potsie," and their relationship was written about by her biographer Craig Unger.

[2] After graduating in 1932, she and a group of female friends formed the Bitch Pack, a sub-culture of local debutantes who enjoyed subverting society events, including lacing punchbowls with mineral oil and performing stripteases on banquet tables.

[10][11] Later in life, she studied in Fontainebleau, France, with Nadia Boulanger, at the Institut Jaques-Dalcroze in Geneva, and the Mannes College of Music, New York.

She also studied orchestration with Lee Hoiby and received a Doctor of Fine Arts degree from the Franklin Pierce College in Rindge, New Hampshire, in 1968.

Her 1955 tone poem, Safari Suite, was performed at Carnegie Hall, and in 1957 she released an album titled Music With a Heartbeat.

Tabloids became fascinated with Harkness due to her alleged eccentricities; supposedly she cleaned her pool with Dom Pérignon champagne and dyed her neighbor's cat green following an argument.

[17] In 1961, Harkness married Ben Kean (c. 1912–1993),[18] a physician who was a professor of Tropical Medicine at the Cornell Medical College.

[22] Harkness' "Holiday House" in Watch Hill was acquired in 2013 by American singer-songwriter Taylor Swift.

[27] Streit interviewed former students and teachers of the school and gathered archival video footage of performances for the film.