A Sister of Mercy, Mary Wickham's ministries included education, writing and the care of the homeless and disadvantaged elderly. Wickham had degrees in theology and English and her interests included Celtic spirituality, Christian feminism and music. She published in periodicals in Australia, the United States of America and Ireland.
Wickham also wrote Music on the Hill : Memories and Voices : One Hundred Years of the Sisters of Mercy and Catholic Education, Casterton 2002 (2002).