The film features an ensemble cast including Kamal Haasan, Jaishankar, Nagesh, Gautami, Rupini, Manorama, Srividya, Janagaraj, Moulee, Delhi Ganesh and Nassar.

He gets in trouble when he arrests four bigwigs – Dharmaraj, Francis Anbarasu, Nallasivam and Satyamoorthy  who escape justice easily and return to take revenge.

He mistakenly believes that she wants to elope with him, but she had actually asked him to be a witness to her marriage with her fiancé Vincent, whom her father disapproves of.

Appu becomes heartbroken and insecure about his height, and he attempts suicide but is stopped by his mother, who then reveals that his dwarfism might have been because of the poison force-fed to her when she was pregnant.

Appu escapes, but Raja and Janaki enter Satyamoorthy's room, having heard the gunshot moments before the inspector arrives.

With Kaveri's silent approval, Appu shoots the rope, causing Dharmaraj to fall and be mauled by circus lions.

In the mid-1980s, Kamal Haasan developed the desire to act as a dwarf in a feature film, and told Singeetam Srinivasa Rao about it.

[12][13] Haasan and Rao developed the "tragic story" of a dwarf who works in a circus, falls in love with a woman who does not reciprocate his feelings, and realises only at the end of the film that she has left him for another man.

[8][15] Afterwards, Haasan and Rao consulted Panchu Arunachalam who said, "you have a unique character – the dwarf; make him the hero and your picture is a hit."

To prevent either character from overshadowing the other, Rao brought in additional plot details like "the whole mistaken identity, tiger dance and romance".

[8] Haasan initially approached Moulee to write the dialogue, but he declined due to other commitments;[16] the position went to Crazy Mohan.

[8] Nagesh, known primarily as a comedian, was initially apprehensive when Haasan approached him to portray Dharmaraja; he feared the film would fail if audiences did not accept him in a negative role.

[16] Ravikanth and Chinni Jayanth appeared in minor roles as Raja's friends, but their portions were deleted from the final cut.

[15][33] The song "Raja Kaiya Vachchaa" had many scenes inspired from Grease (1978), including the transformation of the old car into a new one, and the dramatically changing costumes of the dancers.

[16][34] The song "Ammava Naan" was initially dumped after the script went through changes, but after many days of running successfully in theatres, it was re-included as an added attraction.

[21] The title Apoorva Sagodharargal was taken from the 1949 Tamil film of the same name, an adaptation of the novella The Corsican Brothers by Alexandre Dumas.

[6] V. Ramji of Hindu Tamil Thisai felt the names of the villains – Nagesh's Dharmaraj, Jaishankar's Satyamoorthy, Nassar's Nallasivam and Delhi Ganesh's Francis Anbarasu – were in contrast to their personalities.

[4] Haasan compared the film to Yaadon Ki Baaraat (1973) because it features the concept of "a family being destroyed by the villain, brothers being separated and reunited".

[4] Despite facing competition from other Puthandu releases such as Pudhea Paadhai and En Rathathin Rathame, it became the highest grossing Tamil film at the time, beating the record of Sakalakala Vallavan (1982).

[47] Khalid Mohamed of The Times of India wrote, "Though [Kamal Haasan] dominates the show from the first frame to the last, the ensemble spirit is forever palpable: the ring-rang rock pop music score by Ilaiyaraja and the dynamic camerawork by P.C.

[55] In 2010, Rediff wrote: "Under Singeetham's very able direction, the movie blended mainstream cinema and emotion very well, [...] and marked the beginning of what was to be a long career, for Kamal Haasan, in getting more into the skin of his character, and setting higher standards for himself with the aid of superior make-up and body language.

[58] Malathi Rangarajan of The Hindu noted that Haasan's commitment to playing a dwarf in Apoorva Sagotharargal "helped him scale heights, not many can reach".

[64] In Periya Marudhu (1994), Sodalai (Goundamani) imagines himself as a dwarf similar to Appu and dances to the song "Pudhu Mappillaiku".

[65] The scene where Appu uses a Rube Goldberg contraption to kill Francis Anbarasu was parodied in Thamizh Padam (2010), with Delhi Ganesh reprising his role.