Belcher was also the uncle of future Massachusetts Lieutenant Governor Andrew Oliver and Massachusetts Superior Court of Judicature Chief Justice Peter Oliver, and was the great-grandfather of British Admiral Edward Belcher.
Belcher war der Onkel des späteren Vizegouverneurs von Massachusetts Andrew Oliver und Massachusetts Superior Court of Judicature Chief Justice Peter Oliver, zudem war er der Ururgroßvater des britischen Admirals Edward Belcher.