Andrew J. Hamilton spent several years in the legal profession before entering politics. He served as acting state attorney general and a state representative, gaining experience in state governance. During the Civil War, he sided with the Union, leading to his appointment as Military Governor of Texas. Post-war, he held the position of provisional civilian governor during Reconstruction, focusing on stabilizing the state amidst financial and legal challenges. Hamilton transitioned to judicial roles and later shifted his political affiliation, participating in state constitutional conventions.

Andrew J. Hamilton's political journey reveals an ideologically fluid approach, marked by a surprising shift from supporting black suffrage to opposing it. His tenure as Military Governor of Texas and provisional civilian governor during Reconstruction highlights a calculated strategy to balance regional interests with federal directives. Hamilton's fluctuating stance on civil rights, combined with his service under both Union and Republican affiliations, showcases an intricate blend of loyalty and ideological pragmatism.