Robert Langdon, the protagonist of Angels and Demons, is a professor of art history at Harvard University. He is a highly respected symbologist, which leads Maximilian Kohler to contact him when the body of Leonardo Vetra is found, branded with an Illuminati ambigram. Langdon is characterized as intelligent and capable as he follows the 400-year-old map of clues across Rome to try to rescue the four cardinals and find the antimatter canister. He is also physically capable and highly resourceful; he overcomes significant stress and tribulation, including breaking out of a glass-encased vault, escaping an armed killer numerous times, and jumping from a helicopter without a parachute.

Langdon is also kind-hearted and morally righteous, making him a classic hero. He supports Vittoria when she discovers the devastating death of her father and tirelessly tries to save the four cardinals, weeping over the body of Cardinal Baggia when he cannot resuscitate him. Furthermore, Langdon chooses to not reveal the Camerlengo’s manipulative betrayal, which would damage the reputation of the Catholic Church and devastate its many followers. A romantic connection develops through the course of the story between Langdon and Vittoria, a happiness he earns by respecting Vittoria as an equal.