Born in Kerala, Karuthadathkuni originally began his athletic career as a runner, winning a bronze medal at a state meet in Kozhikode. He then started to play football in 2008 after being convinced to do so by his brother, Pramod. He went on to represent the Kerala under-14 side in 2010 before appearing for selection trials for the AIFF Regional Academy in May 2012. He was able to trial for a spot in the academy after his performances for his state during the South Zone under-16 championship a few months prior. Karuthadathkuni was trialing with 54 other prospects for a spot in the academy. His trial was successful and in the end he was the only player from Kerala to be selected for a spot in the AIFF Regional Academy. He also had a stint with the DSK Shivajians academy.
Kerala Blasters
Karuthadathkuni stayed with the regional academy and eventually moved up to be part of the AIFF Elite Academy for four years. In 2016, he was signed by the Kerala Blasters of the Indian Super League. He made one appearance on the bench for the side during the 2016 ISL season, on 4 November against Delhi Dynamos, but didn't see any game time.
On 14 January 2017, Karuthadathkuni made his professional debut in the I-League for Chennai City against Bengaluru FC. He started and almost played the full match despite Chennai City losing 2–0. He scored his first professional goal of his career for the club on 12 March 2017 against East Bengal. His 92nd-minute goal was the winner as Chennai City defeated East Bengal 2–1.
On 4 July 2017 it was announced that Karuthadathkuni would be retained by Kerala Blasters for the 2017–18 season. He soon made his professional debut for the club, coming on as an 80th-minute substitute in their opening match of the season against ATK. Kerala Blasters would draw the match 0–0. 2018 Hero Super Cup On 6 April 2018, Prashant debuted for Kerala Blasters FC in round 16 of Hero Super Cup 2018. He scored a 48th minute goal, one of two goals the club scored in a 2-3 loss to NEROCA FC.
'''2019-20 season'''
On October 20th 2019, Prasanth started and played the full 90 minutes in the opening game of the Indian Super League 2019-20 season against rivals ATK as the Blasters won 2-1 at home. His cross for Bartholomew Ogbeche in the 45th minute led to the winning goal.
International
Karuthadathkuni has represented India at the under-19 level.
