Human–engaged computing (HEC) opens up new research directions for the study of ideal human–computer relationships. A key concept within HEC—synergized interactions—has emerged as a primary research focus. However, how synergized interactions occur, sustain, and can be systematically realized in concrete interactive processes remains insufficiently articulated. Our study introduces a perspective of rhythm to reveal the critical role of rhythm in achieving synergized interactions. We propose that rhythm-based synergized interactions are observable and computable, and construct a comprehensive theoretical framework comprising three components: (1) state definition: we define synergized rhythms as a determinable state of synergized interactions, and establish a computational framework that includes human rhythms, computer rhythms, interaction rhythms, and synergized coefficients, (2) regulation mechanisms: we propose two types of regulatory pathways: time–point–based synergized rhythms and time–interval–based synergized rhythms, and (3) design principles: we design feedbacks for shallow detection based on time-point adjustments and deep detection based on time-interval adjustments. Our study provides a practical framework and developmental pathways for future theoretical extensions and system design in the field of synergized interactions.