J. Marcus Hadley was born June 15, 1921, in Vermillion County, Illinois. His parents were Milton H. Hadley, a Quaker minister, and Freda Morris Hadley. The initial "J" was deliberately written on the birth certificate; to the family it stood for "Jeremiah," the name of Mark's grandfather, the first of several astronomy enthusiasts in the family.
Coming from a long line of Quakers, Mark attended Quaker summer camp at Duarte Lake, where his father was director; Olney Friends School, where Mark first became familiar with unprogrammed Quakers; and, after graduating from Chicago Junior College, Earlham College, his parents' alma mater. At Earlham he met Marjorie Brown, also a science major, who later became his wife.
As a Quaker and a pacifist, Mark registered as a conscientious objector. During World War II he served in the Civilian Public Service, working in western Oregon in 1943 and then on a U.S. Coast and Geodetic Survey crew in the Southwest until 1946. The experience gave him lifelong bonds with the other men on the crew.
Mark and Margie were married on June 1, 1945. Mark had brief leave from his service, but at the time Margie was suffering an illness contracted in the chemistry lab where she worked. Margie rose from her bed long enough for the wedding ceremony.
After the war, the Hadleys moved to Whittier, California, where they built their first home and started their family. Having majored in chemistry, Mark worked for Mobil Oil and then Philadelphia Quartz Co., advancing from chemist to plant superintendent. In the late 1960's he joined management at Pilot Chemical Co., where he remained until his retirement in 1986. Ever energetic, Mark subsequently undertook a career in real estate.
Mark became a member of the Rotary Club and was active for over 50 years. He and Margie hosted many students through its international exchange programs.
Mark and Margie raised their children, Carle, Jan, and Neal, with gentle persuasion. The family enjoyed frequent activities, travels, and adventures together.
While attending First Friends Church of Whittier, the Hadleys began meeting with other families in unprogrammed worship. The Whitleaf Worship Group later became the Whitleaf Friends Meeting. Mark gave many volunteer hours to the American Friends Service Committee and the Friends Committee on Legislation of California.
Mark and Margie moved to Sacramento in 2001 and transferred their membership to the Sacramento Friends Meeting in April of that year. It was the year the meetinghouse was being built, with volunteers painting the inside and the outside. That summer--the year they turned 80--Mark and Margie came every weekend to paint in the Sacramento heat. They later served on the Building and Grounds Committee and would be found before meeting tending the flowers and plants, Mark always in his Sunday jacket and tie.
Mark was unfailingly cheerful and took a lively interest in other people. Many recall his warm-hearted hello as a meeting greeter. It was Mark who began the meeting custom of greeting newcomers after meeting with a hearty chorus of "Welcome!" as they introduced themselves.
In 2012 the Hadleys left Sacramento to be close to their children in Oregon and, later, Billings, Montana. They continued an active life. Mark died peacefully on October 23, 2019, in the loving care of his family.