 From 1825 until 1832, Simson served as Grand Commander of the Scottish Rite of Freemasonry (Northern Jurisdiction).In 1852, Simson, along with eight other men representing various Hebrew charitable organizations, came together to establish the "Jew's Hospital", the institution that eventually (in 1866) became Mount Sinai Hospital.Its location, West 28th Street between 7th and 8th Avenues in New York City, was on land donated by Simson; he served the first president of its board of directors and personally assumed many of the young hospital's financial burdens.