Levas Kleinas graduated from Vilnius University in 1975 and started working at the Lithuanian National Opera and Ballet Theatre in 1976. Since 1979 he has been the chief Lighting Designer with the LNOBT. During this period L. Kleinas created lighting design for more than 50 operas, including La Traviata, Faust, Nabucco, Turandot, Un ballo in maschera, Rigoletto, Macbeth, Don Giovanni, Carmen, Fidelio, Tannhäuser, Tosca, Otello, Eugene Onegin, Ernani, Cornet etc., and more than 40 ballets, including The Sleeping Beauty, Swan Lake, Giselle, La Sylphide, Coppélia, Romeo and Juliet, Desdemona, Tristan and Isolde etc., as well as many concerts.
In 1986 L. Kleinas toured the Bolshoi Theatre in Moscow (here LNOBT presented 7 different performances), in 1988 – at the Teatr Wielki in Warsaw (5 different performances). Also, together with the LNOBT he has appeared on tours in Germany, Holland, Taiwan, Spain, Savonlinna Opera Festival in Finland, Verdianaeum Festival in Busseto (Italy), Dalhala festival in Sweden.
L. Kleinas has toured a lot with S. Prokofjev’s Romeo and Juliet, conducted by Maestro Mstislav Rostropovich and performed by the LNOBT’s ballet company. The venues include Shlezwig-Holsten Music Festival in Germany (1994), tours in Evian (France, 1997), Thessaloniki (Greece, 1997), Cairo (Egypt, 1997), Washington (USA, 1998), Cagliari (Italy, 1999), Ingolstadt (Germany, 2000), Tokyo and Osaka (Japan, 2001), London (UK, 2002) and others. At the LNOBT L. Kleinas has worked as an assistant lighting designer for Peter Mumford, Rick Fisher, Mimi Jordan, Adam Silverman and others.
In 1998 OISTAT organized the publishing of The New Theatre Words dictionary for the Eastern European countries in their languages. L. Kleinas was one of the three translators who translated the dictionary into Lithuanian language; he also served as the supervisor of special terms.