In 1999, Petrosian won the World Youth Chess Championship in the Boys U16 category. Later, in 2002, he bagged the Armenian Chess Championship title. His team was a bronze medal winner in the 2010 Chess Olympiad.
Petrosian has also made a name in the online chess arena, notably through his participation in various Pro Chess League competitions. His online team, the Armenia Eagles, managed to win the Pro Chess League in 2018.
Petrosian's career is backed by his bachelor's degree in chess coaching from the Armenian State Institute of Physical Culture. He has also written a book, aptly titled “My Career,” detailing his journey in chess. The book includes his successes, failures, and experiences on his journey to becoming a Grandmaster.