Writing about Gustavo Martínez Sierra requires acknowledging, from the outset, that his legacy cannot be reduced to a single voice or a list of accomplishments. His presence is interwoven with the mentorship, academic collaboration, and personal support he offered to those of us who shared various moments of his intellectual life with him. With deep sorrow and gratitude, this tribute brings together three perspectives—that of a mentor, that of a fellow student and colleague, and that of a student who went on to become a colleague—to offer, without claiming to be exhaustive, a glimpse of the indelible mark he left on mathematics education and on our own paths. In these perspectives, we recognize the rigor of the researcher, the generosity of the teacher, and the warmth of someone who knew how to make academic life a place of connection.