Thambi Ramaiah, hails from Rarapuram village in Pudukkottai, and initially entered the film industry hoping to become a screenwriter. His father was a poet and a fiction writer and his mother was a housewife, while Ramaiah was their eldest child. He revealed he earned pocket money during his school days by being the writer of love letters for his classmates, and also had an interest in lyric writing, often wrote lyrics for parody versions of popular songs, while becoming trained in various instruments including the harmonium and guitar. Aged 20, he moved to Chennai and tried to make a breakthrough into the film industry but lack of contacts meant he worked in a private company for nine years. He got a break in 1994 and took up a job as a dialogue writer for a serial on Sun TV, doubling up as an assistant director, script writer and lyricist. He then earned opportunities to work as an assistant director in films directed by T. Rajender and P. Vasu, and he considers the latter his teacher of screenplay-writing. He also made a cameo acting appearance in a scene from Vasu's film Malabar Police (1999) in a scene featuring Goundamani. The following year, he made his directorial debut through Manu Needhi (2000) which starred Murali and Napolean in the lead roles. He carried on portraying supporting roles in films as well as writing comedy tracks, also directing the Vadivelu-starrer Indiralohathil Na Azhagappan (2008).
He made a breakthrough as an actor portraying a friendly cop in Prabhu Solomon's romantic film Mynaa (2010) and won the National Film Award for Best Supporting Actor for his performance. He subsequently won positive reviews for his performances in films including Saattai, Kumki (2012) and Kathai Thiraikathai Vasanam Iyakkam (2014). At the peak of his career in 2013-2014, he worked for up to four films a day, while being on locations for close to twenty five days a month. He also served as his own manager and often was in charge of his own make-up and costumes in films.