Karthi has been involved in several charities and social service activities. On his 31st birthday, he inaugurated the "Makkal Nala Mandram", in order to encourage his fans to become involved in welfare activities. During the event, Karthi donated blood, donated bicycles to handicapped people, sewing machines to women and schoolbags to children. He presented a cheque of 50,000 to YRG Care Centre, which helps AIDS affected children. In 2011, Karthi became a cause ambassador for promoting awareness of lysosomal storage disease. He had also adopted a white tiger cub at Vandalur Zoo and contributed 72,000 to protect and preserve the animal. He told Indiaglitz; "When I see people in need, I make sure I go and help. If I am going on birthdays to reach out to kids in orphanages, it is for my own satisfaction. I feel happier to be with them and it's nice to make them smile on that particular day."