In June 1838, the Lamar family became victims of the Pulaski disaster off the coast of North Carolina, en route from Savannah to Baltimore.

In 1846 the senior Lamar decided to move with Harriet and their family to New York City to expand his business dealings, settling in Brooklyn.

[11] A series of bad investments in gold mines and slaves, combined with the Panic of 1857, caused Lamar to fall deep into debt by 1857.

[14][15] Lamar openly expressed a desire to reopen the slave trade,[16] and next attempted to bypass existing laws by applying to transport passengers from Africa on the ship Richard Cobden.

His cousin Howell Cobb, now serving in the cabinet of James Buchanan as the Secretary of the Treasury, denied three separate applications, deeming each one a ruse to secretly import slaves to the United States or Cuba.

[18] In the summer of 1858, still desperate for money, Lamar led a group of investors to finance an expedition by the Wanderer in order to smuggle in slaves.

The ship was outfitted with large water tanks and other requirements for transporting slaves but passed inspection in New York as a pleasure yacht.

The ship flew the pennant of the New York Yacht Club when it departed the harbor under command of Captain William R. Corrie, who had purchased it.

[19][20][21] Between July and September, the Wanderer sailed from Charleston to the Congo River, evading British and American naval squadrons, where Corrie purchased 487 Africans.

[22] On November 29, the ship returned across the Atlantic and arrived at Jekyll Island outside Savannah, which was owned by the Dubignon brothers, friends of Lamar.

Corrie only had unsigned clearance papers to present for the ports of Trinidad and St. Helena, where the ship had never called, raising suspicion.

In early January, Lamar's father-in-law, Judge Nicoll, ruled the ship had been used for slave trading and ordered it to be auctioned off.

Two other Africans were found shortly after, but Lamar issued a writ of possession for them as his personal slaves while Ganahl was not present in Savannah and was allowed to leave the jail with them, after which they were not seen again.

[28] A series of six trials were held between November 1859 and May 1860, presided over by Associate Justice of the Supreme Court James M. Wayne and Judge Nicoll.

Lamar also engaged in another jailbreak to remove one of the crew members from his cell and take him to a party in Savannah, for which he was charged and pled guilty.

After resigning his commission, Lamar worked with his father in his business interests to keep the Confederate States supplied, including through blockade-running ventures.

[34] After the capture of Savannah during Sherman's March to the Sea, Lamar re-entered the Confederate Army as a colonel on the staff of Howell Cobb, who was now a general.

[37][a] Historians such as Tom Henderson Wells regard Lamar as an effective, if unscrupulous, businessman who acted on principle to defend the slaveholding society.

[41][42] This view has been challenged by Jim Jordan, who writes that Lamar had a poor business record, believed he would profit from the expeditions, and was primarily motivated by financial desperation.

[43] An editor for the North American Review wrote Lamar "insisted, before the public, that that he was fighting for a principle; and so queer a bulb is the human head, that perhaps he thought he told the truth".