Lewis was born in Porciúncula at the Occidental Palace to Crown Prince Lewis, Duke of Newark, later Lewis I of Sierra, and Martha, Duchess of Newark, later Queen Martha of Claremont. As the eldest grandchild of Smith I (the progenitor monarch of Sierra), Lewis II became the heir apparent in the line of succession to the Sierran throne at the age of five in 1893, following the death of his grandfather, and the subsequent ascension of his father. He was educated at the Saint Vibiana Priory School in Porciúncula, and later Santa Monica High School in Santa Monica. Like his father, Lewis pursued his secondary education at The Presidio where he earned his bachelor's degree in medicine before serving the Royal Navy from 1906 to 1910. On his 23rd birthday in 1911, Lewis was named the Duke of Newa