Finding his salary insufficient in the economic turmoil of post-abolition Jamaica he emigrated to Nicaragua and Panama before settling in New York City in 1853.

He found work as a printer before being employed as a science teacher and then assistant principal at the Institute for Colored Youth in Philadelphia, Pennsylvania.

In 1858 Campbell joined Martin R. Delany on the Niger Valley Exploring Party to look for a suitable site for the settlement of black Americans in West Africa.

[2]: 133  Campbell found a position as an apprentice at a printing shop before training as a teacher at the newly established Normal School at Spanish Town.

[1][2]: 134 In 1858 Campbell was invited by Martin R. Delany to join the Niger Valley Exploring Party, an expedition to inspect land around Abeokuta (in modern-day Nigeria) for potential settlement by black Americans disenchanted with the level of racism in the United States.

[3] In his writings Campbell wrote that his prospective emigrants were "willing to seek a home in the land of their forefathers where unimpeded by unjust restrictions they might find the means not only of developing their mental and moral faculties, but promote legitimate commerce and the production of those staples, particularly cotton, which are now supplied to the world chiefly by slave labour" with a hope of undermining slavery and the slave trade.

[3] He hoped to promote commercial development in Lagos but was hindered by continuous war between the tribes of the inland regions which led to blockages in trade along the rivers.

Campbell was one of a number of Lagos residents who petitioned the Colonial Office to install a strong governor to exert control over the interior, suggesting Captain John Hawley Glover.