- Served with the Volunteers as the foreman of California Engine Co. No. 4.
- Appointed 2nd Assistant Engineer, 1866
- Appointed Chief Engineer, July 20, 1870
During the first seven months of the new Department there had been one hundred and fifty nine fires, of which forty four were suspected of being arson.
Matters in the Department had not been running smoothly and the influence of political partisanship was having a demoralizing effect. Chief Ackerson's term of office was of brief duration, and on April 3, 1871, David Scannell was appointed the new Chief Engineer.