Willard Hartup was born on October 27, 1927 in Fremont, Ohio. In 1950, he graduated with a B.S. in psychology and in 1951 with an M.A. in educational psychology, both from Ohio State University. In 1955, Hartup earned his Ed.D. in human development from Harvard University.
Hartup served as an assistant professor in the department of psychology at Rhode Island College of Education from 1954-1955. At the Iowa Child Welfare Research Station at the State University of Iowa, he was named assistant professor in 1955, and associate professor from 1960-1963. Hartup came to the University of Minnesota in 1963 as an associate professor, being named a full professor in 1964. From 1966-1971, Hartup was the associate director of the Institute of Child Development at the University of Minnesota, being promoted to director from 1971-1982. From 1990-1992, Hartup was the Rodney S. Wallace Professor for the Advancement of Teaching and Learning. In 1993, he was named a Regents' professor until his retirement in 1997, when he was named Regents' professor emeritus in the Institute of Child Development.
Over the years, Hartup investigated topics such as mutual animosities among children and adolescents, conflict and aggression in childhood, romantic relationships, imaginary companions, and the benefits of collaborations and friendships. He was acknowledged as a pioneer in the study of peer relationships, and received the G. Stanley Hall Award for Distinguished contributions in Developmental Psychology from the American Psychological Association. He also received a Distinguished Scientific Contribution Award form the Society for Research in Child Development and the International Society for the Study of Behavioral Development. Since his retirement, Hartup and his colleague Richard Weinberg have written a history of the Institute of Child Development to mark its 75th anniversary, and he remains active in exploring issues in child development.
From the guide to the Willard W. Hartup papers, 1958-1993., (University of Minnesota Libraries. University Archives [uarc])
