Aaron Forrester served in Revolutionary War from 1776-1783 with various units. The Pennsylvania Archives have a record of his serving with Mordecai Morgan's Co. of Goshen Township, Chester County Milita entering service on 27 June 1777. This is according to the PA. Archives, 5th series, Volme 5, page 467. In the same book, he is listed as a Sgt. on the roll of the Goshen Township in Capt. John Johnson's Eigth Company, 5th Battalion. His residence at that time is shown as Goshen.
In 1780, he was taxed as a freeman, meaning that he was unmarried and had no dependents. In 1790, he is shown in Franklin County. The census shows that he was married and had three females in the household. This would be his wife, Sarah and daughters, Tamer and Lydia.