Caesar Carpentier Antoine was born in New Orleans, Louisiana, on September 10, 1836, to a prominent Creole family. His family were part of an established network of Creoles of color in Louisiana that fought for public rights and equality. His father, Pedro Antoine, was a veteran of the Battle of New Orleans and his mother, Mary Gasso, was a native of the West Indies. His paternal grandmother, an enslaved woman of color, bought her freedom and made a living as a midwife. Antoine’s family history helps explain why he and his brother joined the 1st Louisiana Native Guards, a state militia unit formed of free men of color for the Confederate Army. As a Creole, Antoine enjoyed relative privilege and freedom in New Orleans, living similarly to his white counterparts, thus aligning some of his interests with those of white Southerners. However, when the Union Army occupied New Orleans early in the Civil War, Antoine joined these forces and recruited Black soldiers. He was forced to relinquish his status as an officer but continued to serve through the Union until the end of the war as a common soldier.

After the Civil War, Antoine returned to his hometown of Shreveport, Louisiana and became involved in business and politics. In 1868, citizens of Caddo Parish elected Antoine to the state senate where he served on the biracial constitutional committee that crafted the Louisiana Constitution of 1868, the most radical document extending civil rights protections to formerly enslaved people and other people of color in the state. By 1872, Antoine ascended to his highest political distinction as lieutenant governor of Louisiana. He remained in this position until Democrats, the White League, and other white supremacists staged a coup to overthrow the election of 1876 and placed a Democratic governor in power. As a result, former Confederates and their allies began to reestablish white supremacist rule in the state government. The coup signified white Southerners’ response to Black political and social gains during Reconstruction, a period in which Black citizens exercised political influence and implemented civil rights laws. One year later, federal troops left their stations in 1877 and marked the end of Reconstruction, leaving Black Southerners without federal protections in the face of growing white supremacist rule. 

Nonetheless, Antoine continued to be an influential activist in New Orleans, where he maintained a residence in the 300 block of South Claiborne Avenue, and worked alongside people of color and progressive white men and women to advocate for equal rights. He held leadership roles in the biracial Unification Movement alongside Aristide Mary and the American Equal Rights Association. In 1891, eighteen Creole of color members of these two groups formed the Comité des Citoyens (Citizens’ Committee) to fight against racial discrimination in courts, including Louis Martinet and Rodolphe Desdunes. Antoine’s experiences defending equal justice during Reconstruction inspired the group to elect him as the Comité’s Vice President. As a veteran voice, his influence was crucial to the organization’s protest of the Separate Car Act and the Plessy v. Ferguson case that eventually reached the Supreme Court.