Carol J. Hodne was born in 1953 in Carroll, Iowa, to Selmer and Phyllis Hodne. Selmer Hodne graduated from the Iowa State College of Agriculture (now Iowa State University) in 1940 with a degree in farm economics. Phyllis Hodne graduated from the State University of Iowa (now the University of Iowa) in 1940 with a degree in sociology. Selmer and Phyllis Hodne married after World War II. Phyllis Hodne maintained the financial records and raised a large garden on the Hodne family farm. Selmer Hodne was an early conservationist, who built terraces in the 1950s. Selmer Hodne traveled to the Soviet Union in 1958 and served on the board of directors of the Iowa Farm Bureau in the 1960s. Carol Hodne described her parents as socially liberal, with her father favoring economically conservative policies that supported free enterprise and small business.

Carol Hodne graduated from Irwin High School in Irwin, Iowa, in 1971. Four years later, she graduated from Iowa State University (ISU), with BAs in psychology and sociology. During this time, Hodne became involved in the women's and anti-war movements. She also helped to organize the women's studies program at ISU, and served as a research assistant for a political science course about women's history.

From 1975 to 1977, Hodne was a full-time volunteer manager of the Women's Community Health Center (WCHC) in Ames, Iowa. The WCHC, a gynecological clinic, was staffed by volunteers and provided health care, sexually transmitted infection testing and treatment, and educational programs on holistic health care and feminist health care. Physicians associated with the Emma Goldman Clinic in Iowa City, Iowa, traveled to Ames to provide abortions at the WCHC. Hodne counseled patients on preventive health care, gave public education presentations, and organized the day-to-day operation of the center until it closed in 1977.

Between 1978 and 1980, Hodne worked as a paralegal in Dubuque, Iowa, where she trained clients and community leaders to effect social change. She specialized in health-related laws, particularly the Hill-Burton Act. She cultivated relationships with labor organizations and rural activists during this period, and was a member of the Dubuque chapter of the National Organization for Women (NOW).

In 1979, Hodne moved to Cambridge, Massachusetts, where she studied community organizing at the Massachusetts Health Care Coalition. She worked to provide access to health care to senior citizens and low-income populations. She spent the next two years in Walker, Minnesota, where she worked as a coordinator on aging for Cass County Social Services, serving as an advocate for people with legal, family, and health problems.

In 1982, Hodne attended a large farm rally in Northfield, Minnesota, and reconnected with activists from ISU; shortly afterward, she returned to Iowa to work as a grassroots organizer for the United States Farmers Association (USFA). The USFA, founded by Fred Stover and Merle Hansen in the 1940s, attracted many progressives who were members of the National Farmers Union. The USFA helped to organize grassroots movements to address commodity prices and debt relief. During this time, Hodne edited Groundswell, a farm movement news journal insert, and counseled farm families on farm credit and price issues. In 1983, Hodne helped organize the North American Farm Alliance (NAFA) in Des Moines and served as the first executive director of the organization. NAFA was comprised of farm activists who built grassroots coalitions with progressive labor, church, and peace activists.

Hodne's work with the USFA and NAFA coincided with the US farm crisis of the 1980s and was often coordinated with other farm organizations of that era, such as PrairieFire Rural Action and the Iowa Farm Unity Coalition. She organized forums, conferences, and protests and wrote articles about the emotional and financial toll the farm crisis took on ordinary farm families. During her tenure as executive director of NAFA, Hodne edited the organization's newsletter; counseled farm families about legal, social, and economic issues; hired and supervised staff; and delivered presentations to policy makers and the general public.

In 1989, Hodne left NAFA to attend graduate school at the University of Iowa. She received an MA in urban and regional planning in 1991, an MA in social psychology in 1994, and a PhD in social psychology in 2000. Between 2000 and 2003, she received postdoctoral training in agricultural health and safety with the Department of Occupational and Environmental Health, College of Public Health at the University of Iowa. Hodne served as coordinator of a project to study environmental and health effects of large animal feeding operations, which culminated in the publication of the Iowa Concentrated Animal Feeding Operations Air Quality Study in 2002. Beginning in 2003, she served as program director for Hodne Heartland Alliance, where she organized science-based public education programming in conjunction with other organizations.