Amos is a highly intelligent church mouse who serves as the narrator of the story. As the oldest of 26 siblings, he is motivated by a strong desire to provide for his large family. Seeking shelter from the cold, he takes up residence in Ben Franklin's fur cap, establishing a contract where he provides intellectual guidance in exchange for regular food deliveries to his relatives. He is fiercely principled and acts as the true brains behind many famous historical innovations.

Ben is a prominent statesman, printer, and scientist who relies entirely on his mouse companion. Though revered by the public for his wisdom and aphorisms, he is privately vain, often lacks common sense, and occasionally behaves foolishly. He honors his agreement to provide a steady food supply to Amos's family, benefiting immensely from the mouse's continuous guidance on science and diplomacy.

Red is a passionate reddish mouse who speaks eloquently and possesses a strong capacity for leadership. He authors a manifesto detailing the grievances of mice against humans, which features stirring language about liberty and justice. Having survived a bitter winter at Valley Forge, he brings deep discipline to his revolutionary ideals.

Sophia is a beautiful white mouse from the palace of Versailles. She lives in exile after a conspiracy forced her out of the French court, which resulted in her husband's banishment and her children's imprisonment. Despite her tragic circumstances and separation from her family, she maintains the poise and grace of a true aristocrat.

General George Washington is the practical commander of the revolutionary army. He requires immediate funds to sustain his fighting forces against the British and seeks out Ben's diplomatic assistance to petition foreign powers for money.

Thomas Jefferson is an American statesman tasked with drafting the colonies' foundational documents. He travels with a fiery mouse named Red, whose rhetoric heavily influences the human politicians' written work.

Madame Brillon is a well-connected French woman who hosts dinners that the American diplomats attend. Unbeknownst to most observers, she wears an elaborate wig that serves as a home for a sophisticated white mouse.