As a young man Merrill had lived with John Muir for a summer, which inspired a lifetime commitment to the outdoors and the Sierra Club. Merrill, who served as Clerk of the Superior Court of Los Angeles, was an active volunteer in the Sierra Club, leading outings for almost twenty years, serving on the Executive Committee of the Angeles Chapter from 1926 to 1935 and on the National Board of Directors of the Sierra Club from 1936 to 1937. When Sam Merrill died in 1948 the Sierra Club named the Echo Mountain Trail after him.