He practiced in South Carolina, where he was elected and served as a member of the state legislature several times.

She was a daughter of Paul Hamilton, the former Governor of South Carolina and U.S. Secretary of the Navy during the War of 1812 under James Madison.

Dawson was also a lineal descendant of Nathaniel Johnson, a former British Member of Parliament, who served as the 14th colonial governor of South Carolina.

Dawson was educated at local private academies before he attended St. Joseph's College in Mobile, Alabama.

After his father's death in 1849, he joined the office of Judge George R. Evans in Cahaba, Alabama, and was admitted to practice in 1851.

In 1886, Dawson was again put forth for the gubernatorial nomination among three other candidates: Henry Clayton, John McKluat, and Thomas Seay.

[2] In August 1886, President Grover Cleveland appointed Dawson as the 3rd United States Commissioner of Education, succeeding former Union Army general and ordained Presbyterian minister, John Eaton,[8] who served under Presidents Grant, Hayes, Garfield, Arthur, and Cleveland.

[10] In April 1887, Columbia College, conferred upon Dawson the honorary degree of Doctor of Letters in token of his "efficient services to the cause of education."

[2] After he left the Education Department, he again returned to the practice of law until August 1892, when he was again elected to the Alabama House, taking his seat in the assembly for the third time as one of the members from Dallas County.

Together, Nathaniel and Mary were the parents of:[2] After the death of his second wife in 1860, Dawson married for the third time to Elodie Breck Todd (1840–1877) on May 15, 1862.