A growing number of bilingual and multilingual national and international students are enrolling in graduate programs in the United States, creating an urgent need to understand how these writers build knowledge of unfamiliar academic genres and become part of their disciplinary academic communities (Selony, 2014). Such students struggle with specific-to-the-discipline composition of written texts, exerting their agency in new academic tasks, and research identity issues. Following an activity theory framework, this case study investigates how three graduate students with diverse educational, cultural, and linguistic backgrounds (Spanish as L1, L2, and heritage language and English as L1, L2, and dominant language) experienced these processes and overcame obstacles by examining (1) the goals as students' understanding of the research project evolved, (2) the construction of students' identities as researchers, and (3) the impact of goals and identity on their investment in learning. Two end-of-semester interviews and 19 reflections over two semesters were collected. The results of a bottom-up content analysis illustrate how the situated and negotiated nature of the writing process aids multilingual writers' transition to more sophisticated academic writing and builds in them a sense of identity as researchers. These findings can serve as a point of departure for developing instructional frameworks that better guide multilingual writers to successfully navigate academia in the United States.