Marion Doherty Hayden was Head of Music at St. Patrick's College, Drumcondra, Dublin for twenty-three years, where she lectured in undergraduate and postgraduate courses, including a Master's degree course in conducting. She directed the college Choral Society and Orchestra in numerous performances, including, most recently, in Haydn's The Creation. In 2008 Marion launched a new Diploma in Choral Conducting in Education and in the Community, which is accredited by Dublin City University.

A graduate of University College Dublin with Honours degrees in both Irish and Music, Marion obtained her Master's degree in Renaissance music from Queen's University, Belfast. From June 2002 to September 2004 Marion was on leave of absence from St. Patrick's College to study for a doctorate in choral conducting and pedagogy at the University of Iowa, USA, under Dr. Timothy Stalter. In 2004 she was awarded the T. Anne Cleary Fellowship for doctoral research and spent four weeks in Switzerland and Bavaria scouring the libraries for information on Romanus Pinzger (1714-1755), the subject of her research. Marion graduated from the University of Iowa with the degree of Doctor of Musical Arts in December 2007.

In 1987 Marion founded Enchiriadis, the prize-winning youth choir, and followed this with Enchiriadis Junior in 1989, and Enchiriadis Treis in 1994. She has conducted her choirs in Germany, Italy, the Czech Republic, Poland, Hungary, Spain, England and the Isle of Man, as well as throughout Ireland. She has also been guest conductor with Cantairí Avondale for performances of Mozart's Requiem, Bernstein's Chichester Psalms, and Haydn's Harmoniemesse. In September 2009 she was appointed conductor of The St. George's Singers in Belfast.

Plans for 2010 include conducting workshops in Edinburgh and conductor-in-residence at the University of Minnesota, Duluth, where she will conduct the world premiére of a new choral work by Dr. Rhona Clarke.