An all-rounder who bats left-handed and bowls right-arm off-spin, he plays for Tamil Nadu in domestic cricket and Gujarat Titans in the Indian Premier League.

[citation needed] Sundar made his first-class debut for Tamil Nadu in the 2016–17 Ranji Trophy on 6 October 2016.

In October 2017, he scored his maiden first-class century for Tamil Nadu against Tripura in the 2017–18 Ranji Trophy.

[14] He had received the Player of the Match award in the first qualifier played between Mumbai Indians and Pune Supergiants, in which he took 3 wickets for 16 runs.

[19] Earlier, he was also added to India's One Day International (ODI) squad for the same series, after Kedar Jadhav suffered a hamstring injury.

[20] He made his ODI debut for India against Sri Lanka on 13 December 2017,[21] his first international wicket being that of Lahiru Thirimanne.

[23] In March 2018, Sundar was selected in India's squad for the 2018 Nidahas Trophy against Sri Lanka and Bangladesh.