Nina Leen (c. 1909–1995) was a Russian-born émigré photographer who worked for Life magazine from 1940–1972, contributing photographs to stories published in 374 issues. Leen’s photography received little attention following her death, as her working method, oeuvre, and character depart from those of the archetypal photojournalist. Using digital reproductions of Leen’s photographic prints and negatives from the Life Photo Collection, a full run of Life, and archival documents housed in the Time Inc. Records at the New-York Historical Society, this thesis evaluates Leen’s contributions to both Life magazine and the field of photojournalism. An introduction, literature survey, and methodological description contextualize Leen’s career. Two appendices and a list of figures present images selected in this thesis, and the issues and sections of Life in which Leen’s photographs were published. Three chapters discuss the beginning of Leen’s career and her typical approach to magazine photography, and two chapters analyze the years leading up to Life’s conclusion as a weekly magazine, when Leen held more command over her output.