D'Souza's professional movie career began, with her Bollywood debut Tujhe Meri Kasam in 2003. Indian film critic Taran Adarsh noted, "Genelia is a wonderful performer. She catches you unaware with a performance that's natural to the core." The movie garnered poor box office returns,and it failed to propel her career in Bollywood. Following her poor debut in Bollywood, she decided to act in South Indian films. Later the same year, she made her Tamil debut as the teenage girl Harini in Boys, a story about five teenagers having stereotypical teen-boy fantasies.