The founder of the Society is artist Sue Ellen Cooper, who lives in Fullerton, California. In 1997, Cooper gave a friend a 55th birthday gift consisting of a red fedora purchased a year earlier at a thrift store along with a copy of Jenny Joseph's poem "Warning." The opening lines of the poem read:

With a red hat that doesn't go and doesn't suit me.

Cooper repeated the gift on request several times, and eventually several of the women bought purple outfits and held a tea party.

Cooper never set out to ignite an international phenomenon. However, after spreading by word of mouth, the Society first received national publicity in 2000 through the magazine Romantic Homes and a feature in The Orange County Register. Cooper then established a "Hatquarters" to field the hundreds of e-mail requests for help starting chapters. She now serves as "Exalted Queen Mother", and has written two best-selling books about the Society.

The Red Hat Society’s primary purpose is social interaction among women, and to encourage fun, friendship, freedom, fulfillment, and fitness. The goal is for members to bond as they travel through life together. The Society is not a sorority or a voluntary service club. There are no initiations or fundraising projects.

A founder or leader of a local chapter is usually referred to as a "Queen". Members are called "Red Hatters". Members 50 and over wear red hats and purple attire to all functions. A woman under age 50 may also become a member, but she wears a pink hat and lavender attire to the Society's events until reaching her 50th birthday. She is referred to as a “Pink Hatter.”

There are two ways of belonging to the Red Hat Society: as a Queen (usually leader of a local chapter; however, no Queen is required to lead a chapter) and as a Supporting Member. Membership dues are paid annually to the Red Hat Society.

Both Red and Pink Hatters often wear very elaborately decorated hats, and attention-getting fashion accessories, such as a feather boa, at the group's get-togethers. The Society's events vary depending on the chapter, but one of the most common pastimes among Red Hatters is attending or hosting a tea party.

Chapters often work together to host large regional events, and Hatquarters hosts several official Red Hat Society events each year.

The official Red Hat Society day is April 25 each year.