With his brothers, James, John, and Joseph Wesley, he founded the Harper & Brothers publishing house. He is credited with founding Harper's Weekly (1850), Harper's Magazine (1850), and Harper's Bazaar (1867). Fletcher gave cartoonist Thomas Nast his start in Harper's Weekly, and gave Nast great editorial freedom.
He founded the publishing house Harper & Brothers with his brothers, James, John, and Joseph Wesley. He is recognized for establishing Harper's Weekly (1850), Harper's Magazine (1850), and Harper's Bazaar (1867). Fletcher gave cartoonist Thomas Nast a start at Harper's Weekly, granting him significant editorial freedom.