John Lindsay, the Mayor of New York City, appointed McGrath as the New York City Commissioner of Correction in 1966.[1] McGrath was formerly Commissioner of Correction in Massachusetts from 1959 - 1965.[1]
In 1970 McGrath oversaw various inmate protests at the Manhattan Central Detention Complex.[2]Ed Koch surveyed the inmates and reported their claims that guards at the prison frequently assaulted them.[2] McGrath was among the leadership who responded to the Attica Prison riot.[3][4][5]