Career
Originally from Ukraine, he immigrated to the United States in 2001. He is currently the fifth-ranked American grandmaster, behind Hikaru Nakamura, Fabiano Caruana, Wesley So, Ray Robson, and Gata Kamsky. Onischuk participated in International Chess Festival Biel 2007, where he placed second after Magnus Carlsen.
He scored 5.5/9 like Carlsen, but lost in the tie-breaker match held after the regular rounds finished.
2007 results
3rd: Aerosvit tournament Phoros
1-2: Biel
2nd: United States Championship
2008 results
1st: Carlos Torre Memorial, Mérida Mexico
1-4: Spice Cup
2nd: United States Championship
3rd: 2008 Chess Olympiad
3rd: Pojkovsky Russia
2009 results
1st: Moscow Open
1st: Open Mexican Championship
3rd: United States Championship
2010 results
1st: Thanksgiving Open Saint Louis
1st: Spice Cup - Lubbock
3rd: United States Championship
1st: Open Mexican Championship
1st: The second board. World Team Chess Championship.