Samuel King and Hannah Goodale were married in Danvers, Massachusetts, on September 30, 1811. The vital records of Danvers, Massachusetts, record the birth of six children: Perley Goodale (1812); Henry Augustus (1813); Samuel Warren (1815); James Putnam (1817); Eben Upton (1828); and a daughter (1831) who died shortly after birth. The family was a wealthy one, and apparently had been so in previous generations. Samuel King is listed in the Danvers section of the publication, Rich Men of Massachusetts as being worth $50,000, "[p]artly [i]nherited." He is described as "a shrewd, money-making farmer." Ebenezer King of Danvers, (probably Samuel's brother) is also included in this list as having a fortune "mostly inherited," of $50,000.

Eben Upton King, the fifth son of Samuel and Hannah King, is the primary correspondent of the collection. Eben was born in Danvers, Massachusetts, on June 26, 1828. Born eleven years after his next oldest sibling, Eben apparently suffered from a variety of ailments, and his correspondence with his parents documents his and their concern over his "ill turns." In 1848, he was a student at Walnut Grove, a school in Lee, New Hampshire, owned and conducted by a Quaker, Moses Cortland. He attended this school until at least 1852, with frequent breaks because of poor health. Eben became a prosperous farmer and in September of 1864, married Mary Louise Trow (called Louise in her correspondence and her own diaries). Entries in Louise's diaries mention three children and indicated their respective birthdays: Hannah, born September 7, 1866, died in 1875; Warren, born August 1, 1870; and a third child, Alice, born March 13, 1875. (There is some question as to whether Alice is Louise's child, as she doesn't mention her birth in her diary entries from the time.)

King died on February 15, 1892, leaving a widow, a son, and a daughter.

Warren King, Eben's and Louise's only son, was born August 1, 1870. He graduated from Massachusetts Institute of Technology in 1893, with a degree in electrical engineering. He became a manager of the Peabody Municipal Electrical Plant. He married Susie Baker in the early 1890s. Their first child, a daughter, was born in 1895.