Classical ballet is a distinctive art form that requires excellent flexibility, postural control, strength, and aesthetic grace. Precise execution of ballet techniques places high demands on the musculoskeletal system, which increase the chance of injury not only during ballet performance, but also during daily living activities. However, little is known about the effects of different levels of dance training on ballet dancers’ gait patterns and lower extremity muscle morphology. The study aimed to investigate the gait patterns and muscle morphology of professional dancers (PD), intermediate level dancers (ID), and controls (ND) using an AI-based markerless motion capture system and ultrasonography. Fifteen participants from each group completed ten gait trials, and their RF, TA, and MG muscles were examined by ultrasonography. The results found that PD displayed greater stride length, faster gait speed, longer swing time, increased hip abduction and knee flexion angle, as well as greater hip external rotation moment peak during gait than ID and ND. Regarding resting muscle properties, PD exhibited greater RF and TA muscle stiffness and better RF and TA muscle quality, as well as longer fascicle length in the right leg RF, TA, and MG muscles than ID and ND. These findings highlight the importance of accurate techniques and level-appropriate training in ballet, as varied mechanical and morphological muscle properties at different stages of training can influence gait patterns during daily activity. Understanding the relationship between ballet training and lower extremity muscle morphology and gait patterns can inform injury prevention strategies and optimize training programs to enhance dancers’ performance and well-being.