In the U.S., 21.8% of adults receive behavioral health treatment annually. In 2024, Medicare began allowing physicians to bill Medicare for certified peer-support specialists through the introduction of principal illness navigation peer-support (PIN-PS) reimbursement codes. An interview study with 20 participants, including physicians, certified peer support specialists and leaders, policy professionals, payer representatives, and behavioral health organization leaders, examined barriers and facilitators to PIN-PS adoption.