Before the devil arrives, Tom does not seem to have a clear source of income. The devil first proposes that Tom become the master of a slave ship, but Tom refuses this offer. Tom then makes a deal with the devil to become a usurer, or a money lender who charges interest. This profession was generally seen as opposed to Christian principles. The devil tells Tom to set up a broker's house in Boston and to charge 2 percent interest on loans, but Tom decides instead to charge an even higher rate of interest—4 percent. Soon, Tom's brokerage house is thronged with customers who are running short on money or who want funds to engage in speculation in buying land and in other pursuits. Tom becomes quite wealthy by squeezing people to repay their loans and by foreclosing on people's mortgages.

At the beginning of Washington Irving's tale "The Devil and Tom Walker," it is unclear what the title character does for a living. The narrator notes that Tom is both "meager" and "miserly." Judging by his house and property, which had an "air of starvation" and was described as a "land of famine," it might best be assumed that Tom did nothing. After his deal with the Devil, however, he becomes a moneylender in Boston. Initially, the Devil wants Tom to outfit a ship and become a slave trader, but when Tom balks at that they settle on Tom becoming a "usurer." When the Devil suggests that Tom lend money at "two per cent a month," Tom insists that he will charge four. Tom's mean and greedy ways eventually make him quite a wealthy man in Boston until, just before he is about to foreclose on the mortgage of a supposed friend, the Devil appears, taking him away to the "black hemlock swamp," and he is never seen again.