Sullivan was concerned with the affairs of charitable organizations and of the First Presbyterian Church. He was a member of the American and New York State Bar associations, many social and scientific clubs, and was the first president of the Southern Society of New York.
Sullivan's concerns encompassed the governance of charitable entities and the First Presbyterian Church. He was a part of several organizations, including professional and social groups like the American and New York State Bar associations, which were involved in various pursuits such as social and scientific endeavors. Moreover, he held the position of president for the Southern Society of New York.