Kalaiyarasan is married to Shanmuga Priya, who he met at Accenture, his first place of employment. He has collaborated with directors Myshkin and Pa. Ranjith, with whom he worked in Madras (2014) for which he received acclaim for his performance. He then worked with director Myshkin on two ventures, Nandalala (2010) and Mugamoodi (2012), and credits the film maker as his mentor. He also played small roles in Ranjith's directorial debut Attakathi (2012), playing the suitor to the heroine, as well as in Vikram Sugumaran's Madha Yaanai Koottam (2013). He first portrayed leading roles in Darling 2 (2016) and Raja Manthiri (2016), but his first high profile project as the protagonist was C. V. Kumar's production Adhe Kangal (2017).