Korolev began his pro career with the Russian club Avtodor Saratov.

Korolev was then selected 12th overall in the 2005 NBA draft, by the Los Angeles Clippers.

Korolev played for CSKA Moscow in the Russian Super League, before joining the Clippers.

[1] He then returned to the Clippers during the preseason, on a non-guaranteed contract, but was waived before the season began.

[9] In October 2014, Korolev signed with the Greek League team Panionios for the 2014–15 season.