[5] Not much is known about Dupont's early life, his family, and how he came to the United States, but documents show that he appears to be educated.

[4][6] When the American Civil War began, Dupont joined Company B of the 13th New Jersey Volunteer Infantry on August 12, 1862.

"[5] After joining the New Jersey Volunteer Infantry, Dupont fought in major battles throughout the war.

It is unknown whether he returned to Jersey City or not, but he eventually ended up at Philadelphia, where he worked as a clerk for a type foundry on Sansom Street.

However, his career at the newspaper was cut short when the Siamese Government hired him as a drillmaster for the Army, acknowledging him as a “young man well up in military affairs”.

[4] He was hired as a foreign instructor, earning him 50 Dollars a month, a very high wage for a commoner at the time.

[3] Dupont left his military career and became a timber dealer, travelling by boat throughout the kingdom's rivers.