Having graduated from the Bratislava Conservatoire in playing the violoncello with Gustáv Večerný and Karol Filipovič and from the Academy of Music and Performing Arts with Jozef Podhoranský Ján Slávik promoted his studies at the Hochschule fur Musik und Darstellende Kunst with Franz Samohyl and Gunter Pichler and reached the finest concept of chamber music. In 1992 he finished his PhD studies at the Academy of Music and Performing Arts where since 1993 he has been building his pedagogical career. In 2002 he became a senior lecturer (docent) in music art – violoncello.
Ján Slávik has taken part in many interpretation courses (Weimar, Kerkrade, Bayreuth, Piešťany) and has been awarded prizes like the Prize for the best interpretation of contemporary music (Prague Spring, 1983), the Prize of music criticism (Young Stage, Karlsbad, 1991). In 2001 he won the Prize of criticism of the Slovak Musicological Association. Ján Slávik belongs to the founding members of the Moyzes Quartet (1975) which between 1986 and 2005 was a chamber ensemble of the Slovak Philharmonic. In years 2006-2007 was Moyzes Quartet chamber ensemble of Modra city. Beginning 2008 is chamber ensemble of Skalica city. With the Quartet Jan Slavik has given concerts in almost all European countries, in Japan, the USA and Canada and produced more than 30 compact disc recordings. As a soloist he has given performances with renowned Slovak orchestras, the orchestra Simfoniette – de Barcelona and the Salzburg Chamber Orchestra. He has given concerts in Germany, Spain, France, Denmark, Austria, Czechia, Poland, Russia and the Ukraine. In year 2006 was Jan Slavik solo cellist in Slovak radio symphonic orchestra. Since 2008 he is a Concertmaster of the Slovak Philharmonic Orchestra.
He was the first Slovak interpreter who together with Daniela Varínska performed the entire work by Ludvig van Beethoven for the piano and cello (sonatas and variations), recorded by Diskant recording house. For Diskant he also recorded 3 CDs of J.S.Bach´s suites and sonatas. Ján Slávik focuses also on interpretation of contemporary music and several Slovak composers ( Iršai, Kupkovič, Zeljenka, ...) dedicated their pieces to him. In the years 1997-2004 he was a member of the string trio Amadé. His conductor partners have been Adolf Vykydal, Bystrík Režucha, Róbert Stankovský, Karol Kevický, Ondrej Lenárd, Leoš Svárovský, Bohdan Warchal, Jack van Steen, Hideaki Umeda, Harald Nerat, Joan Luis Moraleda, Stephen Somary, Harvey Bordowitz, Jerzy Swoboda. He has given concerts in all important Slovak music festivals, abroad he performed in festivals Wurzer Sommerkonzerte (DE), Young Stage Karlsbad (CZ), Festival Haute-Savoi (FR), Vendrell – Festival international de Musica Pau Casals (ES), International Music Festival Ljubljana (SI), Sommerkonzerte Langenargen (DE), Festival Est-Ouest Die (FR), Neue Musik Hannover (DE), etc. He regularly leads master interpretation courses (e.g., 3 summer interpretation courses in Žilina, Clearing of Talents in Dolný Kubín, international interpretation courses in Komárno, or workshops in Žilina and Dolný Kubín). He is the founder of the international mini-festivals of arts - Music for Modra and Music for Trnava. Ján Slávik regularly cooperates with radio and television and records for recording houses Diskant, Marco Polo, Naxos, TUTL and Classico.