The film stars Aarathi, Gangadhar, Rajinikanth, Ramgopal, Udaya Chandrika and Pandari Bai.

In Baalu Jenu, a married woman must try to keep a one-night stand that she had in college a secret from her husband, and thwart a persistent blackmailer intent on collecting money from her to keep quiet about it.

Geetha, a college student in Mysore, has a one-night stand with her rich boy friend Chandru.

Unfortunately Chandru gets arrested on suspicion of abetting his industrialist father in smuggling and is sentenced to five years in prison.

After Geetha graduates, her marriage is arranged; to her surprise, the prospective groom's elder sister is the same doctor who saved her life and knows her secret.

[5] Rajinikanth, after watching Thengai Srinivasan's performance in the original film as a blackmailing photographer, expressed his desire to reprise that role and got it.

[6] Baalu Jenu was also the first film where a character played by Rajinikanth had a major onscreen fight sequence.

He also compared it to many other earlier Rajinikanth films such as Apoorva Raagangal (1975), Munithaayi (a segment of the 1976 anthology film Katha Sangama), Anthuleni Katha (1976) and Moondru Mudichu due to the fact that they focused on a central female character.