Father Malcolm Mark O'Leary, son of the late John O'Leary and Clementine Conway O'Leary was born April 21, 1930, in Sulphur Springs, Mississippi. He was one of twelve children and attended Sacred Heart School in Camden, Mississippi as well as Holy Ghost School in Jackson, Mississippi. Father O'Leary departed this life, May 25, 2022.

Father O'Leary began his formal educational preparation for the priesthood in September of 1947 at St. Augustine Seminary in Bay St. Louis. Upon the completion of his priesthood preparation, at St. Augustine, Father O'Leary entered his novitiate training in Techny, Illinois on September 8 1951. Techny, Illinois is also where Father O'Leary took his first vows in 1953. May 4, 1961, under the authority of Archbishop Vagnazzi , Father O'Leary was ordained into the priesthood at St. Augustine Seminary in Bay St. Louis, Mississippi. Father O'Leary's departure will be felt by many, but family and friends are comforted in knowing that he has now joined the faithfully departed.

Father O'Leary was preceded in death by his parents, John O'Leary and Clementine Conway, six brothers, John Frank O'Leary, Patrick Henry O'Leary, Lawrence "Smitty" O'Leary, James Kermit O'Leary, Eldridge "Tommy" O'Leary, Alfred Wendell O'Leary; three sisters, Selena O'Leary, Annie Mae O'Leary, Mary O'Leary.

He leaves to cherish his memories, two brothers, James T. O'Leary of Alabama and Bernard O'Leary of California; and a host of nieces, nephews, other relatives and friends.