Abraham Herr Smith was born in Manor Township near Millersville, Pennsylvania on March 7, 1815 the son of Jacob Smith, a millwright, and Elizabeth Herr. His parents died when he was eight years old and he and his sister spent the remainder of their childhood with their paternal grandmother. He received early schooling at the Lititz Academy and also studied surveying at the Franklin Institute in Lancaster. After a start at college life at Harrington College, Smith entered Dickinson College in Carlisle, Pennsylvania and joined the class of 1840. While at the College he was a member of the Union Philosophical Society. Following graduation with his class, Smith read law in Lancaster with John R. Montgomery and was admitted to the Pennsylvania bar in October 1842.
He soon established a thriving practice in Lancaster and in 1842 was elected to the State house as a Whig, serving one term. He moved on to the State Senate in 1845 and served there until 1848. In state affairs he was particularly active in fiscal responsibility issues concerning the State debt, compulsory education, and the rights of married women. He also worked for the sale of public works. While in the State Senate he was defeated in an election for Speaker by one vote when, according to reports, he refused to vote for himself.
After a return to lucrative private practice for some years, he was prevailed upon to stand for the congressional seat that his fellow Dickinsonian, O.J. Dickey, had just vacated. He was elected on the Republican ticket in the autumn of 1872 to the seat that the famous Thaddeus Stevens had held before Dickey. He was a success in the Forty-third Congress and was elected to the next five sessions, serving from March 1873 to March 1885. An ardent protectionist, Smith was noted throughout his time in Washington as a rigid economist in all government activities; for example, he supported the direct payment of pensions through the Treasury rather than through agents, as had been the previous practice. He was also vigorously an opponent of silver coinage in anything but fractional small change and of a return to governmental specie payment. He sat on the War Claims Committee for six years and also on the Appropriations Committee. He was not nominated for a seventh term and retired to his practice in 1884.
A strong Methodist, Smith had been selected as a Dickinson College trustee when he was thirty-two years old and served in that position for forty-five years until 1892. He was also a member of the board at Franklin and Marshall College in Lancaster. He never married. Abraham Smith died in Lancaster on February 16, 1894 and is buried in Woodward Hill Cemetery in that city. His surviving sister, Miss Eliza E. Smith, who had become a well known philanthropist in Methodist and Lancaster causes, on his death donated $10,000 to dedicate in the new Denny Hall building the A. Herr Smith Memorial Hall for the use of the Union Philosophical Society.