He was the son of Amzi Doolittle Barber (1810–1901), a pastor of the Congregationalist Church,[3] and Nancy Irene Bailey.

[4] After graduating from college, he briefly considered following his father's vocation in the ministry, but instead took a teaching position at Howard University.

[5] In late August 1902, the newly formed Consolidated National Bank elected Amzi L. Barber, Lyman G. Bloomingdale, and James Newcomb as directors.

[6] In 1873, abandoning teaching, Barber developed LeDroit Park, a neighborhood adjacent to Howard University with his brother-in-law, Andrew Langdon (d. 1919).

Extensive focus was placed on the landscaping of this neighborhood, as developers spent a large sum of money to plant flower beds and trees to attract high-profile professionals from the city.

[12][13][14][15] In 1878, he became actively involved with asphalt pavement work with his brother-in-law John J. Albright, a Buffalo industrialist.

Senator John Sherman for the purchase and sale of the "Stone" property, then on the outskirts of Washington, D.C.[5] This led to an interest in asphalt for paving city streets, after a government study determined it to be the best available method.

"[4] Barber was buried at Oak Hill Cemetery in Washington, D.C.[19] As part of the purchase of the "Stone" property in 1880, Barber reserved the best piece of the property for his own use, and in 1886, commissioned architect Theophilus P. Chandler to design an imposing châteauesque Queen Anne mansion made of stone.

In 1913, Belmont was sold by his son to developer Harry Wardman and razed in 1915 to allow for construction of the Clifton Terrace Apartments.