Born in Burlington, Iowa in 1913, A. Starker Leopold was the oldest son of noted conservationist Aldo Leopold and his longtime wife, Estella Bergere Leopold. His siblings—Luna, Carl, Estella, and Nina—all made contributions to the conservation movement. As a result of his father's employment by the United States Forest Service, Starker Leopold spent some of his youth in New Mexico; when his father began teaching at the University of Wisconsin, the family moved to Madison.

He received his B.S. from the University of Wisconsin in 1936, and then studied at the Yale Forestry School before transferring to the University of California, Berkeley, where he received his Ph.D. in Zoology in 1944. In 1938 he married Elizabeth Weiskotten; the couple had two children.

After working in Mexico for the Conservation Section of the Pan-American Union, Leopold returned to Berkeley in 1946 as Assistant Professor of Zoology and Conservation in the Museum of Vertebrate Zoology. He became professor in 1957. For three years (from 1960–1963) he was Assistant to the Berkeley Chancellor; he also served as Director of the Sagehen Creek Field Station from 1965 to 1978.

In 1962, A. Starker Leopold was appointed as chairman to the Special Advisory Board on Wildlife Management by Secretary of the Interior Stewart Udall. Leopold retained this association until his death twenty years later. The Advisory Board was responsible for writing what is known as the Leopold Report, a series of recommendations regarding wildlife and ecosystem management in the country's national parks. The Report is recognized as a seminal work for the conservation movement.

Leopold was also an active member of numerous conservation committees and organizations, including The Nature Conservancy, Sierra Club, Wilderness Society (of which his father was a founding member), and the National Wildlife Federation.

In addition to the more than 100 scientific papers he authored, Leopold wrote six books during his life. He was elected to the National Academy of Sciences in 1970.