As a concert singer Ágúst has sung solos with conductors like Petri Sakari, Hannu Lintu and Paul McCreesh. Ólafsson participated in master classes given by Dietrich Fishcer-Dieskau and Elisabeth Schwarzkopf as well as having private lessons with both of them. In 2007 Ágúst performed at a Wigmore Hall concert, given by the Elisabeth Schwarzkopf/Walter Legge society, to celebrate the life of Schwarzkopf.
In the 2004 Hugo Wolf Akademie´s international lied competition he and his duo partner, the pianist Izumi Kawakatsu, took second prize. Ágúst and the pianist Gerrit Schuil won the Icelandic Music Award 2011 as Performer of the year for their performance of all three song-cycles by F. Schubert (Schöne Müllerin, Winterreise, Schwanengesang) at the 2010 Reykjavík Arts Festival.