Why did Edgar Degas paint so many ballet dancers?

Edgar Degas’s focus on ballet dancers was driven by his lifelong fascination with the human form and his desire to explore contemporary Parisian life through a radical, modern lens.12

His interest in the subject evolved throughout his career:

• Early Period (1870s): Degas was drawn to the dramatic, high-glamour world of the Paris Opéra, which was also associated with sexual intrigue. He used these scenes to test his skills in a "daring new context," often depicting backstage life through "through-the-keyhole" glimpses that were considered radical and occasionally scurrilous for the time.234
• Artistic Technique: The dance provided a perfect subject for his experiments with composition. Influenced by photography and Japanese prints, he utilized "cut-off" compositions and unconventional angles to give his work a snapshot-like quality while remaining meticulously planned.23
• Later Years: As his career progressed, his focus shifted away from the specific urban context of the theater. His later depictions of dancers became essentially engagements with the human form, exploring rhythmic relationships between bodies and individual presence rather than documentary descriptions of the stage.5

Ultimately, Degas used the dancer as a vehicle to combine traditional draftsmanship with modern, innovative approaches to art.23