Andrew Carnegie’s father, whose struggles to adapt to the Industrial Revolution motivate Andrew to succeed in the industrial world. He briefly appears in the early part of Andrew's life, setting the stage for Andrew’s ambitions.

A superintendent at the Pennsylvania Railroad and a mentor to Andrew Carnegie, helping him learn about modern corporate operations and investment. His complex relationship with Carnegie highlights Carnegie's early career in railroads and business.

A business associate of Andrew Carnegie who becomes a partner in Carnegie Steel. His differing views on labor management and role in the Homestead Strike highlight tensions within Carnegie's business operations.

Andrew Carnegie’s younger brother, who works under him in various industries. His tenure as chairman of Carnegie's company reflects the pressures and challenges faced by those close to Andrew.