Given the amount of time writing instructors spend in providing feedback on writing, researchers have sought to understand many dimensions of feedback, especially the practices that best support student writing development. A number of researchers have sought to understand student perspectives on response to writing, and this study builds on that work by examining student perceptions of responses to writing from a longitudinal perspective. This interview-based study draws on data from college students who were interviewed once each year for five years (four years of undergraduate education and a fifth year in graduate school or the workplace). Conducted at a major private university in the United States, this article draws its data from a five-year longitudinal study of 189 college students (a random sample of 12% of the incoming freshman class) that collected student’s writing in and out of class, and included semi-structured interviews with a subgroup of 39 students once each year during the five-year period. The interviews focused on the students’ writing lives and investigated many aspects of their writing experience both in and out of school. This article presents an analysis of their perceptions of factors that contributed to their development as writers, especially feedback, as the initial coding of the interview data showed that feedback was by far the most influential contributor to student’s writing development. Further analysis of the interviews focused on understanding the who, what, when, where, why, and how of feedback, that is, the analysis sought at a fine-grained level to understand the ways and degree to which feedback contributed to student’s growth as writers. Elements of theories of dialogism and dialectic were particularly useful in highlighting the features of effective responses to writing; specifically, the idea that the most impactful forms of feedback took place when there were frequent and ongoing dialogues between a writer and a responder with a particular set of characteristics. These types of conversations were particularly impactful when conducted with peers outside of classroom settings. Results suggest that future researchers on feedback should look beyond individual instances of feedback to ongoing chains of communication, and to seek to understand the ways in which writers integrate feedback into their writing practices. Results also showed that feedback from peers outside of classroom settings were highly influential on students’ sense of their own writing development. Implications for research and teaching are discussed. Specifically, it is suggested that teachers and those responsible for writing pedagogy are encouraged to consider ways in which they can facilitate multiple, ongoing streams of high-quality feedback for their students, and to prioritize these conversations in their instructional practice and writing pedagogies.