Strong's legal practice thrived during the tumultuous war years, and was one of the most successful in Hampshire County. He became a judge of the Court of Common Pleas in 1775, and was appointed county attorney of Hampshire County the following year, a post he held until 1800. On more than one occasion he was offered a seat on the state's supreme court, but rejected the position on account of its inadequate salary. Strong was described by a contemporary as meticulously detailed in his preparation of legal paperwork and a persuasive advocate when speaking to a jury.