While living in her native Karwar, Leena nursed a dream of becoming an actress in the film industry. She secretly sent her portfolio to studios at the tender age of 15.

When Chandavarkar reached Mumbai, she modelled for a few advertisements. It was through one such advertisement that actor-filmmaker Sunil Dutt noticed her and cast her as a lead in his home production, Man Ka Meet (1969). Veteran actor Vinod Khanna also made his debut in the film, in a negative role. The film was a moderate success but it was the Jeetendra starrer, Humjoli (1970) that catapulted her to instant stardom. The fantastic soundtrack of the film was commended, in particular, the track “Dhal gaya din...” which became an instant hit.

Chandavarkar was by now working with established stars of the era such as Shammi Kapoor in Jaane Anjaane (1971) and Preetam (1971), Dharmendra in Rakhwala (1971) and opposite Rajesh Khanna in H S Rawail's Mehboob Ki Mehndi (1971).  While these films helped maintain her stardom, Chandvankar didn't get the best roles within it. In fact, it was her starring role opposite popular comedian, Mehmood in Main Sunder Hoon (1971) that gained her a lot of appreciation. In 1974, she worked with Jeetendra again in the film, Bidaai (1974). In this film, Chandvankar chose to portray an unconventional character who depicted shades of grey. This role was in direct contrast to her innocent and girl-next-door persona that had established her in the Hindi film industry so far. The film became one the biggest hits of her career and her performance was also greatly appreciated.

By the mid 1980s, Chandavarkar had settled into domesticity and appeared in small roles in films such as Sarfarosh (1985). She continues to live in Mumbai. Her son, Sumeet, with late veteran singer Kishore Kumar, who was over 20 years her senior is also a singer and currently works in Hindi films.