Falch was the son of Michael Melchiorsøn Falch (died 1768) and Mette Marie Heiberg (1699-1766) [REF].
On August 25, 1756 he married again, to Christi(a)ne Margrethe Hagerup (1732-1795), and they had the following children: Anna Sophie Falch (1759-1830), Michael Melchiorsen Falch (1762-?), Hans Christian Falch (1764-?), Melchior Falch (1768-1849), and Cathrine Marie Helene Harboe Falch (1770-1854, who married Hans Knagenhjelm Daae).