She received a Ph.D. in cell physiology from Harvard Medical School in 1993. Heald has done groundbreaking research on the mechanisms of cell division, focusing on the mitotic spindle apparatus, which functions to segregate duplicated chromosomes equally to the two daughter cells. She is using her Pioneer Award to study how cells determine the size of their component organelles, such as the spindle. Heald is a monitoring editor for the Journal of Cell Biology. She was the 2005 recipient of the Women in Cell Biology Career Recognition Award from the American Society for Cell Biology.