John H. O'Brien explained

John H. O'Brien was appointed the fourth Fire Commissioner of the City of New York by Mayor George B. McClellan, Jr. on January 1, 1906 and served in that position until his resignation on October 10, 1906.^{[1] [2]}

Notes and References

1. News: The City Record. 34. 1906. New York. 4796. 5.
2. News: 2019-09-17 . New Fire Head Turns Down Croker's Order . . 1906-01-02 . en-US . 0362-4331.