Born in Baltimore and raised in Catonsville, Father Hemler was inspired to study for the priesthood by the priests he encountered at St. Mark's Church in Catonsville.
He was a teenager when he entered St. Charles Minor Seminary in Catonsville in 1951 and pursued further religious studies at St. Mary's Seminary on Paca Street, and later at St. Mary's Seminary & University in Roland Park.
He was ordained into the priesthood in 1964 by Lawrence Cardinal Shehan at the Roman Catholic Cathedral of Mary Our Queen, and began his career as assistant pastor at St. Stephen's Church in Bradshaw.
In 1965, Father Hemler entered the Catholic University of America in Washington, where he earned both his master's and doctorate in education.
Father Hemler taught religion at John Carroll High School and St. Thomas Aquinas parochial school before being appointed in 1968 as associated superintendent of the department of education for the Archdiocese of Baltimore.
Father Hemler left the position in 1971 when he joined the faculty of St. Patrick Seminary in Mountain View, Calif. Four years later, he moved to St. Stephen Seminary in Kaneohe, Hawaii, where he served in administration at the college.
He returned to Baltimore in 1982 when he was assigned as temporary pastor and administrator at Annunciation Roman Catholic Church in Northeast Baltimore, a position he held for a year, when he was named associate pastor of St. Mark's Church in Catonsville.
Later that year, he was made pastor of St. Anthony Shrine in Emmitsburg, and received an additional pastorate, Our Lady of Mount Carmel in Thurmont, in 1987.
Father Hemler moved to Fallston in 1992 when he was named associate pastor of St. Mark's Church, and five years later, became its pastor.
During his tenure at St. Mark's, he presided over the restoration of parish buildings.
"He was a humble and gentle priest who empowered the people of the parish to take hold of their faith and do things for the church through various ministries," said Charlotte Henderson, St. Mark's pastoral associate.
"He had a great sense of humor with a laugh that resonated everywhere. He had a wonderful bass voice and when he sang, sang beautifully," said Ms. Henderson. "He was my boss and wonderful to work for. He was friendly and warm and people felt that. He made the church very much a family."
During the last two years, Father Hemler refused to let his failing health interfere with his priestly duties. He endured an aortic aneurysm, heart bypass surgery, artery bypass surgery, amputation of a leg and a serious fall that left him bruised.
"I remember after he was recovering at Stella Maris and I was pushing him in a wheelchair that had no bar for his feet. I was afraid that his prothesis might get caught in the rug and asked him to raise his leg," recalled Ms. Henderson. "He responded by saying, 'Lift high the cross.'"
He was determined to give First Holy Communion to the children of the church last spring while seated in his wheelchair, placing the consecrated host in each child's mouth with the words: "The body of Christ."
Bridget Goedeke, who is St. Mark's administrator of faith information, told The Catholic Review, "It was simply the most amazing miracle. I had moms say to me that no one ever did it the way he did. He met the children eye-to-eye. It was beautiful."
Monsignor Thomas J. Tewes, a close friend for a decade, described Father Hemler as a "patient man."
"He was a generous and kind man who suffered well. He suffered what the Lord asked him to do and never gave up hope," said Monsignor Tewes. "He was an innovative priest who was good to young people."
Monsignor Tewes said his friend loved to take cruises and was an avid reader.
"He had a great laugh and was fun to be around. He also was a good cook. It was his hobby," he said.
Father Hemler retired in 2010 and moved to Mercy Ridge in Timonium, where he was living at his death.
In an interview earlier this year with The Catholic Review, Father Hemler reflected on his life's work.
"At St. Mark, I never considered it work," he said. "I loved it so much."
A Mass of Christian burial will be offered at 10:30 a.m. Thursday at St. Mark's, 812 Reckord Road.
Surviving are two sisters, Patricia Hoeck of Baltimore and Bernadette Roeder of Catonsville; and many nieces and nephews.