Mindfulness is often described as the heart of Buddhist meditation. Nevertheless, cultivating mindfulness is not a Buddhist activity.
In essence, mindfulness is universal because it is all about attention and awareness, and attention and awareness are human capacities that are innate in all of us. Still, it is fair to say that, historically speaking, the most refined and developed articulations of mindfulness and how to cultivate it stem from the Buddhist tradition, and Buddhist texts and teachings constitute an invaluable resource for deepening our understanding and appreciation of mindfulness and the subtleties of its cultivation. That is why from time to time, as you’ve seen, I mention various Buddhist teachers and viewpoints, nuanced via the ways in which the various traditions within Buddhism — such as Chan, Zen, Tibetan, and Theravada — have refined different modes of speaking about the deployment of attention and awareness, in addition to having developed a vast range of different meditative practices, which ultimately can be thought of as different doors into more or less the same room.
That said, it is important for us to keep in mind that the Buddha himself was not a Buddhist and that even the term “Buddhism” was coined by eighteenth-century European scholars, mostly Jesuits, who had little understanding of what the statues of a man sitting in a cross-legged posture on temple altars across Asia were really about.