Born in Palanga (Lithuania) finished the Arts Academy in Vilnius in 2002. As of 1998 he has been designing the productions of his father Eimuntas Nekrosius, including Shakespeare's Macbeth (Meno Fortas Theatre, 1999, Golden Mask and UBU Awards); K. Donelaitis's The Seasons (2003) Song of Songs (2004), Goethe's Faust (2006); The Idiot after Dostoyevsky (2009).
In 2000 Marius Nekrosius designed sets for Chekhov's The Seagull within the framework of the international project “School of Masters”. He also designed sets for the productions of Howard Barker's The Europeans (Vilnius, 2002); Anton Chekhov's Ivanov (Argentino Theatre, Rome, 2002), The Cherry Orchard (Mento Fortas Theatre and Stanislavsky International Foundation, Moscow, 2003); Lev Tolstoy's Anna Karenina (Storki Theatre, Modena, Italy, 2008).
In 2002 he was the set designer for Eimuntas Nekrosius's production of Verdi's Macbeth at the Communale Theatre in Florence. A year later it was staged at the Bolshoi Theatre in Moscow. His others works in opera include Desyatnikov's Children of Rosenthal (Bolshoi Theatre, 2005), Musorgsky's Boris Godunov (Magio Musicale Theatre, Florence, 2005), Wagner's Valkyrie (Lithuanian National Opera, 2007); The Tale of the Invisible City of Kitezh and Virgin Phevronia (co-production of Bolshoi Theatre and Cagliari Theatre of Italy, 2008); Gounod's Faust (La Scala, Milan, 2010); Verdi's Othello (Vilnius National Opera and Ballet Theatre, 2011).
In 2005 Marius Nekrosius received Lithuanian Critics Award in the Best Set Design nomination for the production of Song of Songs.