Daboll's early career was that of a teacher. He taught mathematics at the Academic School in
Plainfield, Connecticut. Because of Daboll's ability with mathematics, Samuel M. Green, an early almanac publisher in the
colonies, asked Daboll to calculate almanac entries. Daboll did so, beginning in 1771, under the alias "Edmund Freebetter", before switching to publishing almanacs and registers under his own name. Almanacs were useful instruments in propaganda wars during the American Revolution. Some of Daboll's almanacs contained satirical or factual political commentary, while others didn't. "lunations; eclipses of the luminaries; aspects; judgment of the weather; rising, sitting and southing of the seven stars; sun and moon's rising and sitting; festivals, and other remarkable days; courts; roads" The textbook ''Daboll's schoolmaster's assistant: being a plain, practical system of
arithmetic, adapted to the United States
was published in 1799, and updated with Daboll's Schoolmaster's assistant, improved and enlarged being a plain practical system of arithmetic: adapted to the United States'' in 1814. Its popularity was based, in part, on its practicality: "We were taught arithmetic in Daboll, then a new book, and which, being adapted to our measures of length, weight, and currency was a prodigious leap over the head of poor old
Dilworth, whose rules and examples were modelled upon English customs." Daboll was also quite notable for his maritime navigation school in
New London, Connecticut where he taught navigation and nautical astronomy to as many as 1,500 seamen. In 1811, at the invitation of Commodore
John Rodgers, Daboll instructed midshipmen on the frigate
President. ''Daboll's Practical Navigator'' was published posthumously in 1820 by his long-time colleague Green. Even after his death, Daboll was remembered for his mathematics.
Herman Melville referred to Daboll in his 1851 novel
Moby-Dick: "I'll get the almanac and as I have heard devils can be raised with Daboll's arithmetic, I'll try my hand at raising a meaning out of these queer curvicues here with the Massachusetts calendar." In his 1890 book
The teaching and history of mathematics in the United States, mathematics historian
Florian Cajori described Daboll as one of the "three great arithmeticians in America". ==Personal life==