• People's Artist of Russia (2005) 
• Recipient of the Golden Sofit, St Petersburg's most prestigious theatre prize (2002, 2004 and 2008 and 2011)

Sergei Aleksashkin studied at the Saratov State Sobinov Conservatoire (1982). After graduating from the Conservatoire, he was engaged by the Saratov Academic Theatre of Opera and Ballet. He also trained at La Scala, Milan, from 1983–1984. Sergei Aleksashkin has been a Mariinsky Theatre soloist since 1989.

Roles performed at the Mariinsky Theatre include: 
Ivan Susanin (A Life for the Tsar) 
Ruslan (Ruslan and Lyudmila) 
Boris Godunov, Varlaam (Boris Godunov)
Ivan Khovansky (Khovanshchina) 
Konchak, Vladimir Yaroslavovich and Galitsky (Prince Igor) 
Gremin (Eugene Onegin) 
Rene (Iolanta) 
Kochubei (Mazepa) 
Mamyrov (The Enchantress)
Vasily Sobakin, Malyuta Skuratov (The Tsar's Bride) 
Prince Vyazminsky (The Oprichnik) 
Sea King (Sadko) 
Salieri (Mozart and Salieri)
Yuri Vsevolodovich (The Legend of the Invisible City of Kitezh and the Maiden Fevronia) 
Tsar Dodon (The Golden Cockerel)
Old Gypsy (Aleko) 
General (The Gambler)
Faust (The Fiery Angel) 
Mendoza (Betrothal in  a Monastery)
Rostov, Kutuzov (War and Peace) 
Boris Timofeyevich (Katerina Ismailova)
Sobakevich (Dead Souls)
Flyagin, Storyteller (The Enchanted Wanderer) 
Czar Alexei Mikhailovich (Boyarina Morozova in concert) 
Zaccaria (Nabucco)
Banco (Macbeth) 
Jacopo Fiesco (Simon Boccanegra in  concert)
Grand Inquisitor, Filippo II (Don Carlo) 
Ramfis (Aida) 
Padre Guardiano (La forza del destino) 
Méphistophélès (Faust) 
Lindorf, Coppélius, Dapertutto, Dr Miracle (Les Contes d’Hoffmann)
Leporello (Don Giovanni) 
the King (Lohengrin)

The singer's repertoire also includes Méphistophélès in  Berlioz' dramatic legend La Damnation de Faust and the bass roles in Verdi's Requiem and Shostakovich's Thirteenth and Fourteenth Symphonies.

Sergei Aleksashkin has toured to many countries throughout Europe and the USA, Australia, South Korea and Japan, and he has worked with such conductors Georg Solti, Valery Gergiev, Claudio Abbado, Gennady Rozhdestvensky, Yuri Temirkanov, Mstislav Rostropovich, Marek Jankowski, Rudolf Barshai, Alberto Zedda, Eliahu Inbal, Neeme Järvi, Eri Klas, Mariss Jansons, Alexander Lazarev, Pavel Kogan, Vladimir Fedoseyev, Vladimir Spivakov, Dmitri Kitayenko, Ivan Fisher and Vladimir Jurowski among many others.

He has performed as a guest artist at the Metropolitan Opera (New York), La Scala (Milan), the Royal Opera House, Covent Garden (London), The Royal Swedish Opera, The Finnish National opera and opera houses in Washington, Rome, Hamburg and Lyon. He has sung at top concert venues throughout Europe, among them the Concertgebouw (Amsterdam), the concert hall of the Accademia Santa Cecilia (Rome), the Carnegie Hall (New York) and the Barbican Hall and the Royal Festival Hall (London); he has appeared several times at Salzburg's Easter Festival and festivals in San Sebastian, Baden-Baden, Mikkeli and Savonlinna.

Sergei Aleksashkin's recordings include CDs of the operas The Fiery Angel, Sadko, The Queen of Spades, La forza del destino, Betrothal in  a Monastery, Iolanta, Prince Igor and Shostakovich's Thirteenth and Fourteenth Symphonies.