With his wife, Helen Bigelow Merriman, he was a cofounder of the Worcester Art Museum and served as its first president.

[1][3] Merriman and his wife led the drive to construct a new building for the Congregational Church at the corner of Grove St. and Institute Rd.

Designed by architect Stephen C. Earle in the Romanesque Revival style, it was completed in 1885; today the building is known as the United Congregational Church.

[3] When he died, the trustees wrote that next to Stephen Salisbury III, "the Worcester Art Museum owes most to Daniel Merriman, under whose administration it has won position, prestige, and the confidence of the public".

[3] Merriman served as a trustee for the Worcester Polytechnic Institute, Williams College, and Atlanta University.