In this study, we explore the role of the heavy-quark potential in heavy-quark coalescence, whose probability is expected to be unity at low momentum. To this end, we develop a phenomenological heavy-quark potential based on the constituent quark model that reproduces the vacuum masses of pseudoscalar and vector heavy mesons. Using this potential, we demonstrate its enhancement effect on the coalescence probability. We also investigate how medium-induced modifications of the heavy-quark potential in the quark–gluon plasma (QGP) affect the coalescence process. Our results indicate that the coalescence probability remains close to unity as long as the modification of the potential is sufficiently moderate.