Background: CrossFit could be an innovative alternative for older adults. Traditional strength training is well-established for safety and progressive overload, while concerns exist about overexertion or poor technique in modified CrossFit, especially for those with musculoskeletal or cardiovascular conditions. However, scaled and supervised CrossFit sessions have shown low injury rates and high satisfaction among older adults. Objective: to evaluate the effects of a CrossFit-adapted program on balance and muscular power. Methods: 60 older adults participated in the study. Participants were randomized into two groups: CrossFit-adapted and control. Functional capacity, balance and strength variables were analyzed. The sample size was calculated a priori using G*Power 3.1 software, considering an effect size of 0.25 [medium], α = 0.05, and a power [1–β] of 0.80 for a repeated-measures ANOVA with two groups and three measurement points. Data were analyzed using SPSS Statistics version 25. Results: Significant improvements in balance scores were observed in the CrossFit group compared to the control group. In the Timed Up and Go test, the CrossFit group improved from 9.83 ± 1.3 s to 8.74 ± 1.1 s, [p = 0.002]. Lower limb muscle power increased significantly in CrossFit group across all tests: chair stand test, the stair ascent and stair descent [p < 0.001]. Conclusions: A CrossFit-adapted program can significantly improve functional capacity, balance, and strength in older adults.