Gajanan Mangesh Rege was a student at J. J. School of Art. He later taught there Advertising Art and Ideas. He had also completed B.A. in Philosophy and Psychology. He completed MA in Sociology. He shifted to London and got training in advertising from College for Distributive Trades. He worked for Richard Wood and Partners, an ad agency. After returning to India, he joined as Head, Publicity of Asian Paints.

He developed the idea of a mascot of a naughty boy for Asian Paints. The face of this boy was drawn by R. K. Laxman. This naughty boy with a paint tin and brush started putting paint on various surfaces, even on the bald head of a grandfather sitting in arm chair. The tag line was ,’ Any surface that needs paint, needs Asian Paints.’

Gajanan Rege decided to name the mascot. He arranged a competition with a prize of Rs.250 to name the mascot. Many wrote a letters suggesting different names. The competition’s dead line was extended, and the prize was raised to Rs.500. The period was 1959-60. Out of 47 letters, the selection committee selected the name Gattu. Two readers Rele and Aras shared the prize of Rs.500 for suggesting this name.

Gajanan Rege used to change jobs. He wrote a book Advertising Art and Ideas. Later its Marathi version was published. Gajanan Rege was later associated with Goa Art College. He was a good calligrapher too. He used to review the research dissertations of the students.