He made his breakthrough playing one of the lead roles in Soodhu Kavvum (2013), before gaining critical acclaim for his performances in C. V. Kumar's productions Pizza II: Villa (2013) and Thegidi (2014).

He was also featured in the title card of Chakri Toleti's Billa 2, with a childhood picture of Ashok Selvan used to represent a younger version of Ajith Kumar's titular character.

Featuring alongside an ensemble cast including Vijay Sethupathi, Bobby Simha and Sanchita Shetty, Soodhu Kavvum became a commercial success, with Ashok Selvan being described as "fantastic" in his role of an unemployed graduate.

[7] The film opened to positive reviews and above average box office collections, with a critic noting that "Ashok delivers an outstanding performance".

Portraying a detective, Ashok Selvan featured opposite Janani Iyer, and won positive reviews for his acting in the film.

[10][11] In 2017, he starred in Kootathil Oruthan, which deals with the love story of a middle bencher and its trailer has had a very positive reaction from the audience and the media.

Oh My Kadavule was released on 14 Feb 2020 and was produced by his own banner Happy High Pictures in association with Axess Film Factory.