Sergey was born in 1953 in Moscow, Russia.He pursued a career in journalism, diplomacy, and politics. Sergey worked for magazines «Problems of Peace and Socialism», «Megapolis», «VIP». Later, he chaired the Board of Directors of the «TVC» television channel.Yastrzhembskiy made his mark in Russian diplomacy in Russian Foreign Ministry as Ambassador to Slovakia. He was Press-Secretary to the first Russian President Boris Yeltsin. In 2000–2008 he was aide to President Vladimir Putin and Special Presidential Envoy to the EU.