She was born Carrie Clinton Lane in Ripon, Wisconsin. Catt spent her childhood in Charles City, Iowa, and graduated from Iowa State College (later called Iowa State University) in Ames, Iowa, graduating in three years. She was a member of Pi Beta Phi, the valedictorian of her class, and the only woman. She became a teacher and then superintendent of schools in Mason City, Iowa, in 1885.

In 1885 Carrie married newspaper editor Leo Chapman, but he died in California soon after. Eventually she landed on her feet but only after some harrowing experiences in the male working world. In 1890, she married George Catt, a wealthy engineer. Their marriage allowed her to spend a good part of each year on the road campaigning for women's suffrage, a cause she had become involved with in Iowa during the late 1880s. Catt also joined the Women's Christian Temperance Union.

Catt became a close colleague of Susan B. Anthony, who selected Catt to succeed her as head of the National American Woman Suffrage Association (NAWSA). She was elected president of NAWSA twice; her first term was from 1900 to 1904 and her second term was from 1915 to 1920. Her second term coincided with the climax of the women's suffrage movement in the U.S., and culminated in the adoption of the Nineteenth Amendment to the U.S. Constitution in 1920. NAWSA was by far the largest organization working for women's suffrage in the U.S. From her first endeavors in Iowa in the 1880s to her last in Tennessee in 1920, Catt supervised dozens of campaigns, mobilized numerous volunteers (1 million by the end), and made hundreds of speeches. After the passage of the Nineteenth Amendment to the United States Constitution, Catt retired from NAWSA.

Catt founded the League of Women Voters in 1920 as a successor to NAWSA. In the same year, she ran as the Presidential candidate for the Commonwealth Land Party.

Catt was also a leader of the international women's suffrage movement. She helped to found the International Woman Suffrage Alliance (IWSA) in 1902, serving as its president from 1904 until 1923. The IWSA remains in existence, now as the International Alliance of Women.

Catt was active in anti-war causes during the 1920s and 1930s. From 1919 to 1928, she resided at Juniper Ledge in Briarcliff Manor, New York. She settled in New Rochelle, New York, in 1928. During this period she was frequently recognized as one of the most prominent female leaders of her time. Carrie Chapman Catt died in New Rochelle in 1947 and was interred at Woodlawn Cemetery, Bronx, NY.