Sevian started to play chess at the age of 5 and his first major success came in 2009 when he broke the record for the youngest Expert in USCF history at 8 years, 2 months of age, beating Brian Luo's previous record by over 10 months. On December 9, 2010, Sevian became the youngest National Master in USCF history at 9 years, 11 months, and 23 days, beating Nicholas Nip's record by 3 days. In 2012, he completed all the norms required for the title of International Master (IM) in the space of 6 months. He became an IM after crossing the 2400 FIDE rating mark during Norm tournament in November 2013 in Budapest, thus setting the new US record of 12 years, 10 months.