Named for his grandfather, Gershom Mendes Seixas, Gershom Arnold Seixas was one of ten children born to Joshua and Henrietta Raphael Seixas. Gershom’s siblings included Seraphine and Selina. In 1858, Gershom married Eliza Caroline Kopper in a ceremony in Hoboken, New Jersey. The couple had ten children, including Caroline.