Andrew Carnegie's ambitious and shrewd mother, who is committed to securing her family's success in the upper-class American society.

A jovial and astute railroad executive and investor, interested in Clara's insights into business matters.

The Carnegie family's cook, a formerly enslaved man who becomes a supportive ally to Clara within the household.

Clara's elder sister back in Ireland, who communicates with Clara through letters detailing their family’s struggles.

Clara’s relative who works in a Pittsburgh iron foundry and faces hardships due to company mergers.

A humorless employment agency owner who provides household staff for wealthy families, including Clara's placement with the Carnegies.

An Irish girl Clara meets en route to Pittsburgh, who initially finds Clara's appearance distasteful.

The unmarried daughter of a wealthy neighbor, who tries to capture Andrew Carnegie's interest.

Andrew's younger brother, generally content to follow Andrew's lead in business but aware of familial dynamics.