Harold has won numerous national and international competitions, including first prize in the Vienna Guitar Forum International Guitar Competition (Austria), first prize in the Cordoba Guitar Festival International Guitar Competition (Spain), first prize in the International Competition of 20th Century Guitar Music Interpretation in Lagonegro (Italy), second prize in the Gisborne Music Competition (New Zealand) and third prize in the 9th Sernancelhe International Guitar Competition (Portugal). He has also placed first in the open guitar sections of many Australian national eisteddfods. In 2005, he won the Bernhard Neumann memorial prize for his outstanding results and contribution to the ANU School of Music. He has also been nominated for the prestigious MCA Freedman Fellowship.
He has performed concerts at the 2005 Darwin International Guitar Festival, at the 2006 Sydney Classical Guitar Society Summer School, for the Queensland Guitar Society concert series, for the Saigon Guitar Society, and at the International Condrongianos Festival in Sardinia. Since 2006 Harold has been a member of the Canberra-based guitar quartet Guitar Trek. He was a founding member of the dynamic septet dominantSEVEN, with whom he has toured regional NSW, performed at the Darwin International Guitar Festival, performed a live broadcast for the Australian Broadcasting Corporation, as well as concerts for Musica Viva and the Canberra International Chamber Music Festival. He has appeared twice as a soloist with the School of Music Symphony Orchestra, first in 2004 premiering Nigel Westlake's guitar concerto Shadow Dances under the composer's baton; and for the second time in 2005 with Max McBride conducting Rodrigo's much-loved Concerto de Aranjuez. | 
