Born on 26 April 1963 in Ordzhonikidze, the capital city of North Ossetia-Alania (now: Vladikavkaz in North Ossetia). In 1982 he graduated from the State Ballet School in St. Petersburg, where his teachers included famous dancers of the Russian ballet: Komstantin Sergeyev, Nikolai Serebennikov, Semyon Kaplan, and Irina Gensler. Later that year he was appointed soloist of the Opera and Ballet Theatre in Sverdlovsk (now Yekaterinburg), where he danced the following parts: pas de deux in Giselle, pas de trois in Swan Lake, Tybalt and Mercutio in Romeo and Juliet, Banco in Macbeth, Golden God and Solor in La Bayadère, Don José in Carmen, soloist in Paquita, and James in La Sylphide. In 1987 he joined the Opera and Ballet Theatre in Tbilisi, Georgia in 1987, where his repertoire expanded to include the following parts: Don Basilio in Don Quixote, Armen in Gayané, the Prince in Cinderella, soloist in The Amazon, Otello in The Moor's Pavane, and the title role in The Demon staged by Russian and Georgian ballet masters.
He came to Poland in 1991 and joined the ballet of Opera na Zamku in Szczecin as a soloist. He was appointed as a soloist of the Polish National Opera ballet company in Warsaw in September 1993. From 1996 to 2009 he danced with he Warsaw ballet as a principal, working with such choreographers as Emil Wesołowski, Pierre Lacotte, Krzysztof Pastor, Antal Fodor, Yuri Grigorovich, André Prokovsky, Lorca Massine, Birgit Cullberg, Mats Ek, Zofia Rudnicka, Irek Mukhamedov, Natalia Makarova, Jíři Kylián, and Alexei Ratmansky.
On the Warsaw stage he danced the following parts: Prince Désiré, Blue Bird and Carabosse in The Sleeping Beauty, pas de deux in Giselle, pas de trois and Rothbart in Swan Lake, Parembo in La Gitana, the Prince and Drosselmeyer in The Nutcracker, Benvolio and Tybalt in Romeo and Juliet, Colas and Widow Simone in Ashton's La Fille Mal Gardée, soloist in Pastor's Third Symphony and in Wesołowski's Le Sacre de Printemps, soloist in Fodor's Rossiniana and Carmina Burana, Conjurer in Rudnicka's La Dolce Vita, Porthos in Prokovsky's The Three Musketeers, the title role in Massine's Zorba the Greek, Gypsy in Ek's Carmen, Bridegroom's Father in Kylián's Svadebka (Les Noces), Harnaś and Father in Wesołowski's Harnasie, Karenin in Ratmansky's Anna Karenina. He has given guest performances in Argentina, Brazil, Denmark, France, Germany, Georgia, Greece, Israel, Italy, Norway, Slovenia, and Spain.
After his retirement as a dancer on 1 September 2009 Walery Mazepczyk became a ballet master and assistant choreographer at the Polish National Ballet. He is the recipient of a Silver Gloria Artis Medal for Services to Culture (2015).
He died on 23 June 2023 at a Wyszków hospital after a long cancer struggle. He had remained professionally active almost until his last days, leading the daily classic class with the male members of the Polish National Ballet company.
Pictured: Walery Mazepczyk during his years as a dancer, photo by Paweł Rosłon