Buechner's first marriage was to Marietta Caiarelli, a nurse. They had a son, Terrence, in 1969, and another son, Patrick. In 1990, Buechner married Nancy Chanitz and had another son, Charles. They lived in McLean, Virginia. Nancy died in 2006. Buechner married Andrea Dravo, an attorney, in 2009. They lived in Washington, D.C., prior to Buechner's death in 2020. Buechner died on March 6, 2020, in Washington, D.C.
