Forgrave began his temperance activities in 1908 with the Michigan Anti-Saloon League. From 1912 to 1913 he was the field secretary for the Massachusetts Anti-Saloon League.[1] In 1917 he became the district secretary for the Portsmouth, New Hampshire YMCA.[2]
At the beginning of World War I, Forgrave was a member of the faculty of the War Work Training Commission at the YMCA College. In 1918 he was stationed by the YMCA with American troops in Siberia.[2] After the war he spent two and a half years as the general secretary of the YMCA in Manila.[3]
After leaving the Philippines, Forgrave moved to Springfield, Massachusetts, where he became superintendent of the Central Western district of the Massachusetts Anti-Saloon League.[3] As district superintendent, Forgrave led drives on prohibition law violators in Springfield, Chicopee, North Adams, Greenfield, and Holyoke.[4] In 1922 he was made an assistant to state superintendent Arthur J. Davis. He was elected state superintendent on February 12, 1924.[1]
In his first year as superintendent, Forgrave was tasked with leading the group's campaign for the referendum on the state's liquor enforcement code. Although the question had been defeated by 103,000 votes two years before it passed by a majority of 8,000 under Forgrave's leadership.[2] Following Wayne Wheeler's death in 1927, Forgrave was mentioned as his possible successor as national leader, but he decided not to seek the position.[5]
During his tenure as superintendent, Forgrave made a number of sensational statements against political leaders and law enforcement. In 1924 his accusations that the office of U.S. Attorney Robert O. Harris was lax in enforcing prohibition laws were thrown out by a grand jury for being "vague, misleading and unproved".[4] In 1928, the Massachusetts General Court investigated charges by Forgrave that members of the body held a "wild party" on April 28, 1927, and that liquor confiscated by the Massachusetts Department of Public Safety had been given away.[6] He was unable to produce any strong evidence that such a party occurred and a special investigative committee found his charges unsubstantiated. Forgrave, however, refused to retract his allegations and on July 12, 1928, the Massachusetts House of Representatives voted 97 to 93 to censure him and strip him of his right to act as a legislative agent.[7][8] The Senate rejected the censure amendment 23 to 10 after Senator Hugh Cregg argued that the amendment was illegal, as no individual had ever been censured without a hearing.[9]
Forgrave resigned as superintendent on November 27, 1928, and was succeeded by Gordon C. McMaster.[2] He decided to step down because he was contemplating divorce and he did not want his personal life to reflect upon the organization. In December 1929, Forgrave divorced his wife in Reno, Nevada, and she was granted custody of their only daughter. He married his second wife, Anna Helrich, on February 28, 1930, in New York City. The two resided with Helrich's family in Everett, Massachusetts, until the marriage ended in divorce on October 18, 1933.[10]