In addition to learning the business, farming, hunting and surveying skills of his father, he was educated at the Virginia Randolph Academy.
He joined the company, along with many other young men, such as Jim Bridger, William Sublette, and Jedediah Smith, while his wife and children remained in Virginia.
For eight years Jackson pursued this adventure, fraught with troubles, including harsh weather, difficult terrain, competition from Canadian, British and French trading companies, and both kindness and treachery from the Native tribes.
Many trappers died under the harsh conditions of life in the Rocky Mountains, or by murder at the hands of competitors or native tribes.
Jackson became involved in other expeditions, including to Santa Fe (in present-day New Mexico) and California, both under Mexican control since it had achieved independence from Spain in 1821.
By December 1837, although gravely ill, he managed to write a letter to his oldest son Edward John Jackson, known as “Ned,” asking him to conclude all his business dealings.
While living in London, England, he was convicted of the capital crime of larceny for stealing £170; the judge at the Old Bailey sentenced him to seven years of indentured servitude in the British colonies of North America.
Elizabeth, a strong, blonde woman over 6 feet (180 cm) tall, born in London, was also convicted of larceny in an unrelated case for stealing 19 pieces of silver, jewelry, and fine lace, and received a similar sentence.
They began to acquire large parcels of virgin farming land near the present-day town of Buckhannon, including 3,000 acres (12 km²) in Elizabeth's name.
John and his two teenage sons were early recruits for the American Revolutionary War, fighting in the Battle of Kings Mountain on October 7, 1780.
While the men were in the Army, Elizabeth converted their home to a haven, "Jackson's Fort," for refugees from Indian attacks.
Instead of farming, Jackson responded to William Ashley's advertisement looking to employ men for his and Andrew Henry's new fur trade venture.
Ashley himself brought up an additional 46 men on a replacement boat, and they and the stranded group finally reached Fort Henry.
[13][c] Ashley and the rest of the surviving party traveled by boat downriver, ultimately enlisting aid from Colonel Henry Leavenworth, Commander of Fort Atkinson.
[15] Either David Jackson or his brother George had been appointed commander of one of the two squads of the Ashley-Henry men in this military expedition.
Soon after the rendezvous, Ashley, along with his party taking back the furs, traveled with Smith and William Sublette to near present-day Georgetown, Idaho.
[24] He was at the 1827 rendezvous at Bear Lake, then returned to St. Louis, Missouri, which had become a center of fur trade, with Sublette for a short time.
[25] Jackson returned to the fur country for the 1828 rendezvous, after which he traveled with a party to the Flathead Lake, Montana region, where they wintered.
[27] By early 1831, Jackson was in southeast Missouri's lead belt, attending to his personal affairs and those of his brother George, who died on March 26, 1831.
On April 7, he returned to St. Louis to meet with his partners for a trade trip to Santa Fe, which was controlled by the Spanish.
[28] While in Santa Fe, Jackson partnered with David Waldo, to journey to California to sell the merchandise he had transported from Missouri.
Waldo convinced him of the viability of traveling to California to purchase mules, and to drive them back to Missouri to sell, to yield more profit.
[30] It was decided Jackson would take a group of men directly to California, and travel through the area buying mules.
Young and his group of men would trap along the way to California, and meet up with Jackson in time to drive the mules back to Santa Fe.
[35] Due to the summer heat, many of the mules died on the way back to Santa Fe, which the party reached in the first week of July.
He had never heard from Ewing Young, after leaving him with the substantial amount of cash and property at the Colorado River, but was never healthy enough to return to California to try to collect payment.