Rajalingam (alias Raju) (Sivaji Ganesan) is the son of a wealthy Madurai-based industrialist, Sankaralingam (S. V. Ramadoss). Living with Raju is his driver and friend, Sundaram (Major Sundarrajan). While vacationing in his family estate at Kodaikanal with Sundaram and his family doctor, Gopal (S. A. Asokan), Raju meet Parvathi (Vanisri) and falls in love with her. Gopal too becomes smitten with Parvathi when he meets her whilst conducting her father's medical treatment. Parvathi, who knows Raju through her father, as he is also an accountant of Raju's family estate, reciprocates Raju's feelings. Gopal decides not to reveal his love for Parvathi to Raju for Raju's sake. Raju and Parvathi marry in secret with the help of Gopal and the consent of Parvathi's father. The couple lives together in Kodaikanal without disclosing the knowledge of their marriage to Raju's father, Sankaralingam.
Three months later, Parvathi becomes pregnant. Sankaralingam, fearing for his son's safety, arrives at Kodaikanal and becomes furious upon finding out Raju's marriage to Parvathi. He orders his henchmen to set the estate on fire with Parvathi and her father inside. Raju and Gopal rush to save Parvathi, but they are stopped by Sankaralingam's henchmen and are forcefully taken back to Madurai, leaving Parvathi and her father for dead. A few months after returning to Madurai, Raju is forced to marry his cousin Vimala (Sowcar Janaki). After the marriage, Sankaralingam hands over his business affairs to Raju and dies. Nineteen years pass. Despite having the mutual affection for each other, Raju and Vimala remain childless and Raju is unable to forget Parvathi.
Sathyamurthy (Sivakumar), a nineteen-year-old who lives with his uncle Murugan (V. S. Raghavan), is unable to retain any job due to his honest nature. He becomes acquainted with Gopal, with whose recommendation he becomes Raju's personal house servant. When Sathyamurthy displays his mother's photograph at his house to pray for her, it is revealed that Sathyamurthy is the son of Raju and Parvathi. Parvathi had survived the accident, was cared for by Murugan and died a few years after giving birth to Sathyamurthy without divulging the identity of Raju to Sathyamurthy and Murugan. Sathyamurthy improves his reading and writing skills with the help of Sundaram's daughter, Gowri (Bharathi Vishnuvardhan) and the two fall in love. When Raju learns of their love, he approves of their marriage. Gopal comes to know that Sathyamurthy is Raju's son, but dies of a sudden heart attack before revealing it.
Jealous of Sathya Murthy's influence on Raju, Rathnam (V. K. Ramasamy) and his wife (Manorama) hide Vimala's diamond necklace in Sathyamurthy's suitcase in an effort to get rid of him. Vimala, upset at losing her necklace, searches the house for it. When Raju, Sundaram, Gowri, and Sathyamurthy return after attending a conference in Kodaikanal, Vimala, acting on Rathnam's provocation, orders that Sathyamurthy's suitcase is searched. When the necklace is found in it, Raju throws Sathyamurthy out of his house, despite Sathyamurthy proclaiming his innocence. Gowri then shows Parvathi's photograph to Raju, who is shocked to learn that Sathyamurthy is his own son. Raju reveals the truth about Parvathi to Vimala, who also accepts Sathyamurthy as her son. Before Raju and Vimala rush to bring Sathyamurthy back, Raju learns of a fire breaking out in one of his mills. Sathyamurthy, unhappy of being wrongly accused by Raju, attempts suicide by entering the burning mill. Raju saves Sathyamurthy in time and reveals the truth about his birth to him. The family is united and Sathyamurthy marries Gowri.
Sivaji Ganesan wanted A. V. Meiyappan to produce his 125th film, which eventually became Uyarndha Manithan. Meiyappan then asked the director duo Krishnan–Panju to search for a good script. One of Meiyappan's friends, V. A. P. Iyer, suggested Meiyappan to remake the Bengali film Uttar Purush (1966). After watching the film, Meiyappan was impressed with it and made a decision with Krishnan-Panju and Javar Seetharaman to remake the film with a few alterations.
When the script was ready, Meiyappan's sons and the film's co-producers M. Saravanan, M. Kumaran and M. Murugan narrated it to Ganesan at his residence, Annai Illam. Ganesan initially rejected it as he felt the character of Dr. Gopal had more impact than the main character, Raju, and sought to film the portions involving Dr. Gopal in four days. However, on Meiyappan's insistence, Ganesan played the role of Raju. The role of Dr. Gopal went to S. A. Ashokan and Ganesan assisted him for acting in the scene where Dr. Gopal dies of a heart attack. S. V. Ramadoss was cast as Raju's father Sankaralingam, Major Sundarrajan as Raju's classmate, Vanishree as Raju's wife Parvathi, Sowcar Janaki as Raju's cousin Vimala, Sivakumar as Raju's son Sathyamurthy, and V. S. Raghavan portrayed Sathyamurthy's uncle Murugan.
When M. Saravanan asked about Ganesan's salary to Ganesan's younger brother V. C. Shanmugham, who spoke on Ganesan's behalf, Shanmugham said that Ganesan was willing to accept any amount that AVM Productions could afford to offer. Taking this to be a vague statement as Shanumgham did not state Ganesan's salary properly, Saravanan discovered that Ganesan accepted ₹200,000 (US$26,667 in 1968) for one of A. P. Nagarajan's latest films. Since Thiruvilaiyadal (1965), Nagarajan's films were made in Eastmancolor, and because Uyarndha Manidhan was made in black-and-white and costume designing for the film was less as compared to those of Nagarajan's films, M. Saravanan decided to pay ₹150,000 (US$20.000 in 1968) to Ganesan. P. N. Sundaram served as the cinematographer, while Panju edited the film under the pseudonym "Panjabi".
Ganesan's mannerisms and acting style in the film were inspired by one of his friends who was a Coimbatore-based industrialist. During the scene near the end of the film in which Ganesan enters a burning house, which he did without any hesitation, he accidentally singed his body hair. The song "En Kelvikkenna Badhil" was re-shot as Meiyappan was not pleased with the earlier sequence that was shown to him by the production unit. The song "Paal Polave" was initially meant to be shot at Kodaikanal, but due to unfavourable weather conditions the production crew decided not to include the song in the final version. The film's art director, A. K. Sekhar, wanted to include the song in the film after hearing its rendition by P. Susheela and constructed a specially erected set at AVM studios in Chennai that resembled Kodaikanal. The song was filmed there in three days.
It was speculated that a film producer bought the remake rights of The Parent Trap (1961) in Hindi and titled it as Vapas. AVM Productions had already acquired the rights to the film, which they were making under the title Do Kaliyaan (1968). To avoid a clash with that film, AVM Production stalled the production of Uyarndha Manithan for eight months and managed to release Do Kaliyaan first. Ganesan, who thought that the project had been shelved, went to inform AVM Productions that he would commence filming with another technical crew. However, AVM Productions convinced him that the shooting was only delayed, and paid him ₹50,000 (US$6,667 in 1968) in advance. After the release of Do Kaliyaan, filming was resumed and completed. The final length of the film's prints were 4,591 metres (15,062 ft) long.
In his 2015 book Madras Studios: Narrative, Genre, and Ideology in Tamil Cinema, Swarnavel Eswaran Pillai notes that the title Uyarndha Manithan, meaning "A Honourable Man", epitomises the contradiction within the character of Raju, and in the trajectory of the rebel in Parasakthi (1952), as he finally ends up a "meek/reactionary family man" who had forsaken his own offspring/lineage at a critical juncture.
The soundtrack and musical score for Uyarndha Manithan were composed by M. S. Viswanathan, while the lyrics were written by Vaali. The soundtrack was released under the label of Saregama. In the composition and picturisation for the song "Andha Naal Gnaabagam", Viswanathan was inspired by one of the songs in My Fair Lady (1964), in which Rex Harrison sings with a walking stick in hand on a golf course. Due to T. M. Soundararajan's laughter being inadequate during the recording of this song, Viswanathan himself recorded his own laughter. M. Saravanan, in his book AVM 60 Cinema, described the use of dialogues in "Andha Naal Gnaabagam" as "something new to Tamil cinema". The song was parodied by Vikram and Vivek in Dhool (2003), and "Paal Polave" was parodied by Santhanam in Yuvan Yuvathi (2011).
The soundtrack was received positively by critics, with "Andha Naal Gnaabagam" and "Paal Polave" remaining popular today in Tamil Nadu. In his book Pride of Tamil Cinema: 1931 to 2013, G. Dhananjayan wrote that Uyarntha Manithan "had memorable songs from the combination of [M. S Viswanathan and Vaali]. The songs [...] are popular even today". Malathi Rangarajan of The Hindu praised the bossa nova portions in the song "Velli Kinnamthan". News Today described "Andha Naal Gnaabagam" as "testament to the capabilities of two legends - TM. Soundarajan and Sivaji Ganesan", adding that the "transition from Sivaji panting and TMS taking over is seamless".
All lyrics written by Vaali.
Uyarndha Manithan was released on 29 November 1968. It earned positive critical feedback and went on to become a commercial success, completing a theatrical run of 125 days. The 125th day commemorative celebrations were held in the presence of C. N. Annadurai, the then Chief Minister of Tamil Nadu. This was also the last function which Annadurai attended before his death.
G. Dhananjayan appreciated the performances of the cast and the quality of Javar Seetharaman's dialogues, calling them "crispy". On Ganesan's performance, Ananda Vikatan, wrote in its 1968 review of the film: "Can anyone show both hate and love at the same time? Sivaji proves that he can! No more than words of 'natural acting' is enough for Sivaji". The magazine praised the film by stating that it "attracts our hearts".
Baradwaj Rangan of The Hindu, when asked by an anonymous person how someone like Sivaji Ganesan can be called a great actor, replied, "Watch Uyarndha [Manithan] and Motor Sundaram Pillai, and let’s continue this conversation." Historian and columnist Randor Guy labelled Major Sundarrajan's performance in the film, along with his role in Gnana Oli (1972), as "memorable".
The National Film Award for Best Female Playback Singer was introduced in 1968. Since Susheela won the first award for her rendition of "Paal Polave", Uyarndha Manithan became the first Tamil film to win a National Film Award under the Best Female Playback Singer category. It was also Ganesan's first film to win a Tamil Nadu State Film Award.
After the success of Uyarndha Manithan, AVM Productions was keen to remake it in Hindi and approached Dilip Kumar. After watching the film, Kumar was hesitant to play the lead role as he felt he would not match Ganesan's performance in the original version. K. Balachander was signed up to be the director of the remake, which led to Kumar being initially convinced that he could be successful.
After a fortnight, Kumar met Balachander in Chennai and watched Uyarndha Manithan again for a second time to study his character. This time, however, Kumar hesitated to portray Ganesan's role and requested Balachander to direct the remake of Babu (1971). Balachander showed concern with Kumar's change of heart and refused the offer, leading to both the remakes of Uyarndha Manithan and Babu being shelved.
The song "Andha Naal Gnaabagam" was considered one of the most memorable songs written by Vaali that featured in a Sivaji Ganesan film. Rediff ranked it alongside "Madhavi Pon Mayilaal" from Iru Malargal (1967) and "Potri Paadadi Penne" from Thevar Magan (1992).
Susheela chose "Paal Polave" along with "Unnai Ondru Ketpen" and "Paartha Gnaabagam Illaiyo" as her favourite songs that she had recorded. Singer Swarnalatha, who made her debut with the song "Chinnanchiru Kiliye" from Neethikku Thandanai (1987), was chosen to sing the song by M. S. Viswanathan after he was impressed with her rendition of "Paal Polave", which he had asked her to sing during the song's audition. The song was rendered twice by the contestants of the fourth season of the Star Vijay reality show Airtel Super Singer, and once each by the contestants of the second and third season of its junior version, Airtel Super Singer Junior.
Ganesan's biographer T. S. Narayanswami included Uyarndha Manithan in his list of Ganesan's "all-time greats". In March 2009, Sharadha Narayanan of The New Indian Express rated Sundarrajan's performance in the film among his other noted films in which he featured like Vennira Aadai (1965), Major Chandrakanth (1966) and Gnana Oli. In her review of the 2011 film Seedan, Malathi Rangarajan of The Hindu said that the premise of the film was "on the lines of Sivaji Ganesan's poignant Uyarndha [Manithan]". Uyarndha Manithan was included with other Sivaji Ganesan-starrers in the compilation DVD 8th Ulaga Adhisayam Sivaji, featuring Ganesan's "iconic performances in the form of scenes, songs and stunts". It was released in May 2012.