Lionel Moses was the son of Joshua and Sarah Rodriguez Brandon Moses and brother to Joseph, Isaac Jr., Israel, Abraham and Benjamin. Raised in New York, Lionel, like his father and his grandfather, Isaac Moses, was involved in the China trade, traveling to Macao on business several times. In 1857 he married Selina Seixas, granddaughter of Gershom Mendes Seixas. They had seven children, including Blanche, Sarah and Gershom Arnold, whom they raised in New York.