He ran for a state senate seat in 1911 but withdrew himself from the race in August 1911 and instead ran for the Assembly. He was a member of the New Jersey General Assembly in 1911 and 1912, and appointed a member of the New Jersey State Water Supply Commission from 1912 to 1915. Geran was assistant prosecutor of the pleas of Monmouth County from 1915 to 1917, and was again a member of the Assembly in 1916 and 1917 and served as minority leader. He served as Sheriff of Monmouth County, New Jersey from 1917 to 1920. One odd event during his tenure as Monmouth County Sheriff was the sale of liquor in 1920. He was ordered by the New Jersey court to sell off the effects of a bar to settle a creditor demands. However, most of the effects of the bar were intoxicating beverages of various types. He was able to obtain federal permission to legally sell the holdings during prohibition.