As a high schooler, Adithan Arunachalam tutored a sixth grade student who was heavily impacted by the COVID-19 pandemic. He also volunteered, during the COVID-19 pandemic, to provide support for his school’s systems administration tasks and helped guide faculty through a system wide migration to the UBUNTU operating system.

Adithan also founded and captained his school's cricket team, in addition to playing for the school’s soccer team. He helped organized the cricket team’s practice sessions and developed match strategies. He did the same for the soccer team, while, also mentoring the junior schools' teams during the summer. Over his four years on the teams, he earned numerous player-of-the-match accolades.

Adithan Arunachalam was also co-founder and co-president of his school's Debate Club. He grew the club until approximately 25 percent of the student body had joined. While attending KC High, he also interned at Professionals Forum, a non-profit social service organization.