in English from Princeton University in 1989[6] after completing a 91-page-long senior thesis titled "A Study of Thomas Stearns Eliot and Wyndham Lewis.

[10] She left her careers in corporate law and consulting for a quieter life of writing at home with her family,[11] likening her years as a Wall Street lawyer to "time spent in a foreign country".

[13] Saying that most introverts aren't aware of how they are constantly spending their time in ways that they would prefer not to be and have been doing so all their lives, Cain explained that she was trying to give people entitlement in their own minds to be who they are.

[15] She said she was interested in working with parents and teachers of introverted children and to re-shape workplace culture and design, and in particular replace what she terms "The New Groupthink" with an environment more conducive to deep thought and solo reflection.

[5] InformationWeek's Debra Donston-Miller had noted that the idea of introversion and extroversion was being widely discussed due in large part to media coverage of Quiet.

Within a year of her first TED talk, Cain had formed an online public speaking and communication class for introverts, said to emphasize authenticity over showmanship.

[30] In 2018, she began co-curating the Next Big Idea Club with Malcolm Gladwell, Adam Grant, and Daniel H. Pink, focusing on books about psychology, business, happiness, and productivity.

[34] More specifically, the organization formed an online education course for parents, a co-branded lifestyle section in HuffPost, a podcast, a website to support a community including writers and advocates, and young-adult books and shows whose heroines are quiet leaders.

Cain's third TED talk (2019), "The hidden power of sad songs and rainy days", preceded her April 5, 2022 book, Bittersweet: How Sorrow and Longing Make Us Whole.

[4] The book's theme is to accept feelings of sorrow and longing as inspiration to experience sublime emotions—such as beauty and wonder and transcendence—to counterbalance the "normative sunshine" of society's pressure to constantly be positive.