As president of the Council in 1945, Kerrigan became acting Mayor of Boston upon the inauguration of Maurice J. Tobin, who had been mayor since 1938, as governor. Initially with limited authority, Kerrigan was given full mayoral powers by the Massachusetts legislature on January 25, 1945.
In 1945, Kerrigan held the position of president of the Council while Tobin, who had been mayor since 1938, became governor. Initially with limited authority, Kerrigan was given full mayoral powers by the Massachusetts legislature on January 25, 1945.