In this paper I explore the significance of the initial decade of Robert K. Merton's graduate and professional career, from 1931, when he entered the new doctoral program in sociology at Harvard, until 1939, when he joined the Department of Sociology at Tulane University as an associate professor and acting chairperson. Drawing on archival sources, as well as the professional literature, I examine how Merton engaged the exceptionally rich, interdisciplinary context of Harvard in the 1930s, including both interpersonal networks and diverse intellectual perspectives. In particular, I identify connections between Merton's early writing, "oral publications" and teaching, and three locally developed and dominant paradigms of sociology. Following an assessment of the influence of Merton's works published from 1934 to 1939, I trace continuities between Merton's achievements at Harvard and his subsequent teaching and research at Tulane and Columbia. I conclude that a fuller appreciation of Merton's "less noticed" decade in Cambridge is indispensable for understanding his overall career, and that it clarifies linkages across sociological work at three universities in the mid-twentieth century.