Produced by Kavithalayaa Productions, the film stars Kamal Haasan, Seetha and Gemini Ganesan.

Manorama, Janagaraj, Prasad Babu, Nassar, and Delhi Ganesh play supporting roles.

Unnal Mudiyum Thambi focuses on the ideological conflicts between 'Bilahari' Marthandam Pillai, a reputed Carnatic musician, and his younger son Udayamoorthy.

Pillai's discrimination towards the people belonging to lower caste is met with criticism from Udhayamoorthy, who believes in society's welfare and walks out for good later.

Adolescent Udayamoorthy, from a high society family, sees an old, blind beggar woman struggling to pick up a banana thrown by a passerby.

Now an adult, Udayamoorthy is a very mischievous and happy-go-lucky guy who likes to pull pranks on his family members and gets punished by his father Bilahari Marthandam Pillai, an ardent devotee and short-tempered Carnatic music singer.

Angayarkanni, hurt by the mischief, feels sad for not playing her role as a sister-in-law and not raising Udayamoorthy properly and making him as an irresponsible boy.

Udayamoorthy finds a lot of men laying always at drunkard state and their children going for work to earn for their drinking expense instead of going to school.

Udayamoorthy and Lalitha together start 'Amaidhi Puratchi Iyyakam' (Silent Revolution Society) and bring many reforms.

Udayamurthy becomes famous overnight and gets 'Best Indian' award from the prime minister for transforming the village in the good path.

[6][7][8] Gemini Ganesan was cast as the Carnatic musician Bilahari Marthandam Pillai, reprising his role from the Telugu original.

"Maanida Sevai", continues from Patnam Subramania Iyer's composition, Pancha Nadeesha Pahimam, set in Poornachandrika.

[2][15] The Indian Express wrote, "[Unnal Mudiyum Thambi] has not only something to say, the manner in which it says this is, within the parameters of Tamil cinema's idiom, quite lively.