An interest in the natural world, combined with the logic of science and math, attracted Lynch-Stieglitz to science and after a summer at the Duke University Marine Laboratory she decided on a career in physical oceanography. In 1986, she earned B.S. degrees in physics and geology from Duke University and for two years she worked as an oceanographer at the Pacific Marine Environmental Laboratory. From 1988 until 1989 she worked at the Maryland Science Center and as a programmer at Johns Hopkins University before moving to Columbia University where she earned an M.A. (1991) and Ph.D. (1995) in geological sciences. After two years as a postdoctoral scholar at Woods Hole Oceanographic Institution, in 1996 she returned to New York where she joined the faculty of the Lamont–Doherty Earth Observatory. In 2004, Lynch-Stieglitz moved to the Georgia Institute of Technology where she was promoted to professor in 2010.
From 2012 to 2015, Lynch-Stieglitz was the Editor of Earth and Planetary Science Letters.
In 2015 Lynch-Stieglitz was elected a fellow of the American Association for the Advancement of Science "for bringing physical oceanography approaches to the study of transient circulation changes during ice ages, providing a window into the ocean’s interaction with today’s climate change."