Norman Wait (N.W.) Harris was born in 1846 in Massachusetts and was interested in business from an early age. After several initial business ventures he moved to Cincinnati to cofound the Union Central Life Insurance Company. He married three times; by his first wife Jacyntha Vallandingham he had two sons (Albert Wadsworth Harris and Norman Dwight Harris); by his third wife Emma Susan Gale he had three children (Pearl Emma Harris (MacLean), Hayden Bartlett Harris, and Stanley Gale Harris). By 1881 N.W. had left the Union Central Life Insurance Company and moved his family to Chicago, where in 1882 he was to found the N.W. Harris & Co. Investment Bankers (a very lucrative business which eventually became the Harris Trust and Savings Bank in 1907). N.W. and Emma Susan Gale Harris wrote each other often, and there are many courtship and love letters in the collection between the two. After a trip with his wife to Japan, N.W. Harris fell ill and died in 1916 at the Harris' summer home, Wadsworth Hall, in Lake Geneva, Wisconsin.

N.W. Harris' youngest son, Stanley Gale Harris, was born in 1890 and went to the Hill School around 1904, then to Yale University. He wrote almost daily to his parents and especially to his sweetheart Muriel Bent, who he married in 1913. After Yale Stanley worked at Harris Bank, but then enlisted during World War I, joining the 124th Field Artillery as a Lieutenant. After seeing action in France and Luxembourg, Stanley remained in Europe through 1919, then came back to work at Harris Bank for the rest of his career, working at various times as the West Coast representative in San Francisco, the New York City representative, and back to Chicago as Vice-President and later Chairman. Stanley and Muriel had four children: Charity Bent Harris, Ruth Harris, Stanley Gale Harris Jr., and Cynthia Harris.

The earliest materials in the collection are land deeds signed by the Harris family and their ancestors for parcels of land in Berkshire County, Massachusetts from the 1780s through the mid-1800s.