Halász was born in Chicago, Illinois, on May 15, 1964, and took up the guitar at eight, also studying violin for a time. Most of his training was in Germany; he attended the Musikhochschule Cologne with Eliot Fisk, and earned support from the DAAD German scholarship body and the European Chamber Association. Halász graduated in 1991, and two years later he won the Andrés Segovia Competition in Spain. He was the first German winner of the competition. After several more major prizes, Halász became professor of guitar at the Leopold Mozart Conservatory in Augsburg, Germany, in 1996; he later taught at the Hochschule für Musik Nürnberg-Augsburg, the Staatliche Hochschule für Musik in Detmold, and, since 2010, the Hochschule für Musik und Theater in Munich. He has given master classes all over Europe, in New York, and in Boston. Halász is married to pianist Debora Halász, and the pair have performed as the Halász Duo. In recital he has also appeared with such artists as Boris Pergamenschikov and Siegfried Jerusalem. Halász is a fixture of German summer festivals including the Brandenburgische Sommerkonzere and Kissinger Sommer, as well as the Toru Takemitsu Memorial Concerts in Tokyo. Halász's concerto credits include appearances with the European Chamber Orchestra and the Tapiola Sinfonietta. He has recorded for the BIS and Naxos labels, and his output has included complete cycles of the guitar music of Takemitsu, Joaquín Turina, Hans Werner Henze, Astor Piazzolla, Bach, Mompou, and Sofia Gubaidulina, among others. Halász's 2014 recording Alma Brasileira won the 2015 Latin Grammy award for Best Classical Album. In 2019, he released an album of Bach's Suites for lute on BIS; it was the first recording to present these works in their original keys.