Her father was a clarinet player and member of the Ghana Army before emigrating to the United States to attend graduate school.

[13] In June 2018, Saint John left Uber to join Endeavor as chief marketing officer.

[25][26] Netflix named Saint John its new chief marketing officer on June 30, 2020, making her the third CMO for the company in 2019–2020.

[3] Saint John wrote a memoir titled The Urgent Life, in which she describes her work as a marketing executive, losing her husband, and becoming a single parent.

[30][31] In January 2021, Saint John taught a short intensive program (SIP) for MBA candidates at Harvard Business School called "Anatomy of a Badass".

[33] Saint John launched the #ShareTheMicNow Instagram initiative alongside Luvvie Ajayi, Glennon Doyle, and Stacey Bendet.

Saint John took over the Instagram account of prominent Black women including Elaine Welteroth, Angelica Ross, Christine Michel Carter, and Gia Peppers took over the accounts of white women including Julia Roberts, Elizabeth Warren, and Diane von Fürstenberg.

[34][35][36][37] Saint John's philanthropic efforts include representing Pencils of Promise as a Global Ambassador to Ghana and serving on the boards of Girls Who Code and Vital Voices.

[38][39][40] Saint John has been a member of the President's Advisory Council for Wesleyan University, her alma mater.