Ionov has participated in numerous chess competitions and has had several prominent victories. He won the Minsk International chess tournament in 1988 and the Championship of Moscow in 1990. In 1992, he took first place at the Russia Chess Championship. He has also taken top honors in competitive events in Denmark (1992) and Norway (1993). His other notable victories include wining the Chigorin Memorial tournament in 1997, the Black Sea tournament in Sochi in 1998, and the Moscow Open in 2009.
In addition to his playing career, Ionov has also served as a coach for other chess players. He has produced several instructional chess videos in Russian, and has also worked as a grandmaster-in-residence at the Botvinnik School in Moscow. He is not to be confused with the similarly-named Russian Grandmaster Sergei Ionov.