: Total knee arthroplasty (TKA) improves balance performance in patients with osteoarthritis; however, balance deficit and fall incidence after TKA have been reported. This study aimed to determine the effects of combined balance exercises on knee range of motion (ROM), balance, gait, and functional outcomes during the acute phase after TKA. : A total of 42 participants were randomly assigned to either the combined balance group ( = 21) or the general physical therapy (control) group ( = 21). The combined balance exercise group performed exercise programs for 30 min per session, five times a week for 4 weeks (20 sessions), and the control group completed general physical therapy, which included active simple exercise. Measurements were performed before and after the 4 weeks of training to assess changes in the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), knee joint ROM, static balance, timed up-and-go (TUG), and 10 m walk test (10 MWT). : The combined balance exercise group demonstrated significant improvements post intervention ( < 0.05) for all outcomes. The time × group interaction effect for the WOMAC scores showed statistically significant interaction effects for pain, stiffness, and physical function; the static and dynamic balance values showed statistically significant interaction effects for CEA, PL, AV, and TUG; and gait ability showed a significant interaction effect for the 10 m walk test ( < 0.05). : This study confirmed that combined balance training with general physical therapy has a positive effect on ROM, static and dynamic balance, gait, and functional outcomes in the acute phase post TKA and that combined balance exercise can be proposed as a rapid rehabilitation intervention with general physical therapy following TKA.