He was the first black person to be elected to the New York State Assembly, be appointed an assistant district attorney or be named a criminal court judge in the Bronx.

[10] In 1957, he was appointed by Mayor Robert Wagner to a judgeship in the New York Criminal Court serving in both the Bronx and Manhattan and presiding over the Adele Morales case.

[5] IN 1948 he was elected to be vice-chairman of the Bronx Committee of the National Conference of Christians and Jews,[14] and was on the board of directors for the Forest Neighborhood Houses.

The Parks Department noted that, "His legislative priorities included combating narcotics use among youth, improving housing for low-and middle-income constituents, strengthening civil rights guarantees and enforcement, and advocating for a state-sponsored summer camp program".

Gladwin retired as a judge in 1972, after which he moved to Highland Mills, New York where he resided for the rest of his life and was in private practice until 1983.