Helen Leland Witmer was born and raised in Pennsylvania. She graduated from Dickinson College in 1919, and earned master's and doctoral degrees from the University of Wisconsin, followed by postdoctoral work at the London School of Economics and Bryn Mawr College. After working as a high school teacher and a statistician, she became an assistant professor of Sociology at the University of Minnesota. In 1929, she joined the Smith College School for Social Work as Director of Research, a position she held for 20 years. She helped set standards for social work theses, edited the Smith College Studies in Social Work, and conducted research for various state and national social service and mental health agencies. She became a founder of the children's welfare model in the United States. From 1949-1951, she was Director of Fact-Finding for the White House Conference on Children and Youth. In 1951, she became Director of Research for the Children's Bureau of the U.S. Department of Health, Education & Welfare. During her 16 years with the agency, she wrote extensively in her field, publishing books and articles on juvenile delinquency, pediatric psychiatry, family welfare, daycare, parent education, adoption, and child guidance.