Ada Deer was born in Keshena as a member of the Menominee Tribe. Her mother was a strong advocate for Native American rights, and Deer followed in her footsteps. She was the first Menominee to earn an undergraduate degree at the University of Wisconsin (UW). In 1961, she was the first Native American to receive an M.S.W. from the Columbia University School of Social Work. Her work on behalf of the Menominee led to the Menominee Restoration Act of 1972, which officially returned the Menominee Reservation to federally recognized status. Because of this accomplishment, Deer became the first woman to chair the Menominee Tribe in Wisconsin.

Her political activism included running for Wisconsin secretary of state in 1978 and again in 1982. In 1992, she became the first Native American woman in Wisconsin to run for U.S. Congress. In 1993, Deer was appointed assistant secretary of the U.S. Department of the Interior, as head of the Bureau of Indian Affairs; she was the first Native American woman to hold that position. While in office, she helped set federal policy for more than 550 federally recognized tribes. As an educator and social worker, she taught classes at the UW-Madison School of Social Work and, in 2000, she became director of the American Indian Studies Program.

In 2018, Deer became the first person to participate in the Culture Keepers/Elders-in-Residence Program at UW-Madison, which seeks to improve the experiences of Native students across campus by building relationships with an older and honored Native leader. Deer also served as chairperson of the Native American Rights Fund and was active in many other community activities.

Because of her groundbreaking accomplishments, Ada Deer received many awards, and in 2019 she was inducted into the Native American Hall of Fame. In 2023, Governor Tony Evers proclaimed August 7 to be Ada Deer Day in Wisconsin.

Ada Deer passed away on August 15, 2023.