Chicago Fire generally portrays LGBTQ+ characters positively, integrating them as valued members of the firehouse and community. Characters like Darren Ritter are depicted with dignity, agency, and supportive relationships, affirming the worth of LGBTQ+ lives without resorting to stereotypes or negativity.

Chicago Fire has featured transgender characters in guest roles, notably Denise (S3E17) and Jamie (S5E10). These portrayals address challenges like misgendering and family acceptance with empathy. The show consistently frames obstacles as external, with main characters acting as allies to ensure the dignity and respectful treatment of trans individuals, contributing to a net positive impact.

The show consistently portrays Christianity as a source of moral guidance, community, and personal strength for many characters. It depicts adherents finding solace in their faith during times of crisis and embodying virtues like compassion and self-sacrifice, without significant narrative critique of the religion itself.