To evaluate the effect of adding integrated core and graduated resistance upper limb exercises to inpatient cardiac rehabilitation program in patients with acute sternal instability after coronary artery bypass grafting (CABG). This was a single-center, randomized, controlled, parallel-group intervention study. This study was conducted at the National Heart Institute. Forty post-CABG patients with sternal instability aged 50-60 years completed this study and were randomized into two groups: an intervention group (n = 20) and an active control group (n = 20). The intervention group (A) received a routine inpatient rehabilitation program from the first postoperative day plus integrated core and graduated resistance upper limb exercises, which started from the seventh postoperative day for approximately four weeks, while the control group (B) received only the routine inpatient rehabilitation program. Sternal separation measured by ultrasonography, visual analogue scale for measuring pain, and activities of daily living (ADL) index were main outcome measures. Patients in the intervention group (A) showed a significant reduction in sternal separation from the supine and long sitting positions, while those in the control group (B) showed a significant increase in sternal separation (p = 0.0001). Both groups showed a reduction in pain, and an increase in the ADL score was observed in Group A. There was a significant interaction between the time and group effects (p = 0.0001). Adding integrated core and graduated upper limb exercises to inpatient cardiac rehabilitation for patients with sternal instability after coronary artery bypass grafting significantly improved sternal healing, pain, and ADL.