After attending the district schools he began studying medicine with a physician of Ridgefield, Dr. Nehemiah Perry, and later completed a course at the College of Physicians and Surgeons in New York City, from which he was graduated with honors in 1815.
For the fourteen years he practised medicine in New York City, and in addition to his private practice, served by appointment as resident physician of the New York Alms House. About 1826 he became interested in India rubber, and utilizing his knowledge of chemistry, conducted numerous experiments in an endeavor to produce a practical rubber compound. He was granted a patent on January 31, 1829; gave up his practice, and moved with his family to North Salem, N. Y. There, using all his savings, he erected factory buildings and installed machinery made after his own design, intending to manufacture rubber goods. Within a short time, however, he abandoned the whole project. Concerning this venture, he said, years later, "So far as I know, I was the first person who attempted to utilize rubber by combining other substances with it, but I did not happen to stumble upon the right substance" (Bishop, post, II, 563).
While in attendance at the Alms House, Howe had become acquainted with the slow and tedious process of making pins by hand, the occupation of many of the inmates, and he was aware that a machine to make pins had been invented in England in 1824. During the winter of 1830-31, in his abandoned rubber factory, he undertook his first serious experiments looking toward the designing of a pin machine and made his first rough model. Having little mechanical experience, he turned for aid in 1832 to Robert Hoe, who was then manufacturing printing presses of his own design. In the course of this year he built in the Hoe establishment a working model of a machine that would make pins – though in an imperfect way – and patented the device. The machine was exhibited that year at the American Institute Fair in New York, where Howe received a silver medal "for a machine for making pins at one operation. "
Financed by his brothers-in-law, Jarvis Brush and Edward Cook of New York, he built a second and better machine in the winter of 1832-33 and then went abroad to obtain foreign patents, which he secured in France, England, Scotland, and Ireland in 1833. After spending another year in England demonstrating his machine and unsuccessfully trying to sell patent rights, he returned to the United States early in 1835, considerably in debt. By the close of the year, however, he had brought about in New York the organization of the Howe Manufacturing Company. He himself was made general agent in charge of manufacture. Within eighteen months five pin machines making "spun head" pins were made and put into production.
In 1838 the company moved to Birmingham, in the town of Derby, Connecticut, where cheaper water power was available, and a few months later Howe perfected the rotary pin machine on which he had started work while in New York. This machine, patented in 1841, made solid-head pins, and with minor improvements continued in use for over thirty years. One of this type is now in the National Museum, Washington. The designing of a machine to stick pins into paper, next in importance to the perfecting of a pin-making machine, resulted from the joint work of Samuel Slocum, DeGrasse Fowler, and Howe, the latter inventing in 1842 a device to crimp the paper into ridges through which the pins were stuck. With one of his employees, Truman Piper, Howe was joint patentee, June 10, 1856, of a process of japanning pins.
After rounding out thirty years of active management of his company, he retired and lived the rest of his life in Birmingham, Connecticut, where he died.
He was married May 20, 1820, to his cousin, Cornelia Ann Ireland of New York.