Dennis Michael Davidson was born May 30, 1939 in Detroit, Michigan. Reared as an American Baptist, he became a Unitarian Universalist in 1964. His degrees include: B.S. in engineering (U.S. Naval Academy 1960), M.D. (University of Michigan 1971), M.A. in Social Ecology (University of California, Irvine 1987), M.Div. (Starr King School 1992), and Ph.D. in Health and Social Psychology (UC Irvine 1995).
He was a line officer in the U.S. Navy from 1960-1966, serving the year 1966 in Qui Nhon, Vietnam. He was a naval medical officer on active duty from 1971-1977 and on reserve status until his declaration as a conscientious objector in 1991. He was awarded the Navy Commendation Medal for directing the Indochinese Refugee Camp in 1975. He completed a cardiology fellowship and the Robert Wood Johnson Clinical Scholar program at Stanford University from 1977-1981. He subsequently served on the medical faculties of Stanford University and the University of California. He received the Preventive Cardiology Academic Award from the National Institutes of Health and authored the book Preventive Cardiology.
In 1992, he was ordained by the UU Church of the Larger Fellowship. He has served as President of the UU Peace Fellowship and editor of its newsletter, UNIPAX. He has been a member of the National Council and Executive Committee of the Fellowship of Reconciliation, the largest interfaith peace organization. He was a Visiting Scholar at Harvard Divinity School from 1995 to 1997, researching the early history of Unitarian and Universalist peace activism.