As a bookkeeper
Rockefeller at age 18
In September 1855, when Rockefeller was sixteen, he got his first job as an assistant bookkeeper working for a small produce commission firm in Cleveland called Hewitt & Tuttle.[35] He worked long hours and delighted, as he later recalled, in "all the methods and systems of the office."[36] He was particularly adept at calculating transportation costs, which served him well later in his career. Much of Rockefeller's duties involved negotiating with barge canal owners, ship captains, and freight agents. In these negotiations, he learned that posted transportation rates that were believed to be fixed could be altered depending on conditions and timing of freight and through the use of rebates to preferred shippers. Rockefeller was also given the duties of collecting debts when Hewitt instructed him to do so. Instead of using his father's method of presence to collect debts, Rockefeller relied on a persistent pestering approach.[37] Rockefeller received $16 a month for his three-month apprenticeship. During his first year, he received $31 a month, which was increased to $50 a month. His final year provided him $58 a month.[38]
As a youth, Rockefeller reportedly said that his two great ambitions were to make $100,000 (equivalent to $3.37 million[39] in 2024 dollars) and to live 100 years.[40]