Callahan is a name of Irish origin that means "bright-headed" or "warrior." People with the name Callahan are often described as intelligent, determined, and charismatic individuals. They have a natural charm and presence that draws others to them. Callahans are known for their strong sense of justice and will always stand up for what they believe is right. Overall, Callahan is a powerful and dynamic name that signifies strength, leadership, and a strong moral compass.