Cain graduated from Princeton University with a Bachelor of Arts degree in English in 1989 and earned her Juris Doctor degree from Harvard Law School in 1993. She worked first as an attorney, and then as a negotiations consultant as owner and principal of The Negotiation Company. Cain has been a fellow and a faculty/staff member of the Woodhull Institute for Ethical Leadership, an educational non-profit organization.
Cain left her careers in corporate law and consulting for a quieter life of writing at home with her family. She later wrote that she looks back on her years as a Wall Street lawyer "as time spent in a foreign country."
When asked what she would be doing if she were not a writer, Cain explained that she would be a research psychologist, saying she is insatiably curious about human nature. Cain's interest in writing about introversion reportedly stemmed from her own difficulties with public speaking, which made Harvard Law School "a trial."
While still an attorney, Cain noticed that others at her firm were putting personality traits like hers to good use in the profession, and that gender per se did not explain those traits. She eventually realized that the concepts of introversion and extroversion provided the "language for talking about questions of identity" that had been lacking.
Cain explained that in writing Quiet, she was fueled by the passion and indignation that she imagined fueled the 1963 feminist book, The Feminine Mystique. Cain likened Introverts today to women at that time—second-class citizens with gigantic amounts of untapped talent. 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.
Cain added that for her, Quiet was not just a book but a mission. Specifically, she said she was interested in working with parents and teachers of introverted kids 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.
The Chicago Tribune noted that Cain, a self-described introvert, grappled with her own introversion as a Wall Street attorney before writing Quiet. In contrast, Cain described the time of creating Quiet, seven years of reading, researching, and thinking, as "total bliss."
Seven years in the making, Cain's book, Quiet: The Power of Introverts in a World That Can't Stop Talking, was published January 24, 2012.
Cain's research was published in articles in the year leading up to the book's publication and in the ensuing months. In her talk at the February 2012 TED Conference, Cain confirmed her April 2011 prediction that the ensuing year would be her Year of Speaking Dangerously—for which the self-described introvert declared she would be training, "as if preparing for a marathon," to be the best and bravest speaker she could be.
Cain later wrote that her year of preparation had unfolded in "three stages of accelerating dread." Cain joined Toastmasters, and as her TED talk approached she scheduled a two-hour crash course with TED's speaking coach. But saying her butterflies had turned into "gut-wrenching knots," Cain worked for six full days with an acting coach immediately before the talk. Three months after the talk, Cain wrote that she had metamorphosed into what she termed an "impossibly oxymoronic creature: the Public Introvert," with Wired's Steven Levy remarking that "the introvert aced the talk." The TED Talks video received its first million views faster than any other TED video, and within nine months had entered the 98th percentile (20th of 1380 videos) of most viewed TED videos of all time.
Nathan Heller's Culture Desk piece in The New Yorker listed Cain's talk among five key TED Talks exemplifying the appeal of that lecture series, citing Cain's presentation of a counterintuitive data-based argument as a miniature theatre piece. About the time of its first anniversary, Harvard Business Review's Mitch Joel listed Cain's TED Talk among "10 TED Talks to Help You Reimagine Your Business." The Atlantic's Megan Garber remarked that the ideas spread by TED are becoming defined by the persona of the speaker who presents them, citing Cain in particular as representing the idea of the power of introversion in an extrovert-optimized world.
Within one week of its publication, Forbes' Jenna Goudreau noted that Quiet was featured by several major media outlets and was shared extensively across the Web, Goudreau observing that readers said they felt validated and seen for the first time. Days before Quiet reached No. 4 on The New York Times' Bestseller List, InformationWeek's Debra Donston-Miller had noted that the idea of introversion and extroversion is being widely discussed right now due in large part to a new book whose author "is making the media rounds."
Following Quiet's publication, Cain spoke at leadership, management, training and education conferences, including engagements throughout the U.S. and internationally By the end of 2012, when Quiet had been named in numerous "Best of 2012" book lists, Cain was named one of five top Princeton alumni newsmakers for that year, and had been featured in the PBS-AOL Makers video initiative for recognizing trailblazing women.
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.
Toastmasters International named Cain recipient of its 2013 "Golden Gavel Award," said to be given annually to an individual distinguished in the fields of communication and leadership. She also received Harvard Law School's "Celebration 60" Award in September 2013, and in May 2014 was listed in Inc. magazine as being on a list of the 50 most influential leadership and management experts.
Cain was one of the "TED All-Stars," presenting for a second time at the organization's thirtieth anniversary conference in March 2014.
Cain collaborates with Steelcase to design office spaces to include quiet areas where workers can have privacy for a time, in contrast to open plan offices.
In 2016, Cain co-authored Quiet Power: The Secret Strengths of Introverts, which focused on introverted children and teens, the book also directed to their educators and parents.
Cain's second TED talk (2014) formally announced the Quiet Revolution—a "venture backed, mission-based" organization for transforming office architecture to combat the erosion of focus and privacy in modern offices, forming a Quiet Leadership Institute to help organizations train introverted leaders, and empowering quiet children. The organization focuses on areas including children, life, and the workplace, while providing training programs and learning tools for client organizations to use in managing employees. More specifically, the organization formed an online education course for parents, a co-branded lifestyle section in The Huffington Post, a podcast, a website to support a community including writers and advocates, and young-adult books and shows whose heroines are quiet leaders. Quiet Revolution implemented a Quiet Ambassador initiative, for which it trained volunteers to be embedded in schools, businesses and other participating organizations."Quiet: The Power of Introverts / How to thrive in a world that can't stop talking" Psychology Today, (WebCite archives for first, second, and third pages of list having links to 73-entry blog series, dated from March 7 through December 23, 2011).
"The Rise of the New Groupthink" (WebCite archive), Opinion section of The New York Times, January 13, 2012; appearing in print January 15, 2012.
"Don’t Call Introverted Children ‘Shy’ " (WebCite archive), Time Psychology section, January 26, 2012.
"Secrets of a Super Successful Introvert: How to (Quietly) Get Your Way" (WebCite archive), O: The Oprah Magazine, February 2012.
"Why the world needs introverts" (WebCite archive), The Guardian, March 13, 2012.
"Introverts run the world – quietly" (WebCite archive), CNN.com, March 18, 2012.
"Revenge of the introverts: It's often assumed extroverts do best in life, but a new book reveals quite the opposite..." (WebCite archive), The Daily Mail, March 25, 2012.
Essay: "An Introvert Steps Out" (WebCite archives of pages 1 and 2), "Sunday Book Review" section of The New York Times, published online April 27, 2012. Version appeared in print on page BR27 of the "Sunday Book Review" on April 29, 2012.