[2] His father was a Presbyterian minister for forty years, and his paternal grandfather was the first college-educated doctor in western Pennsylvania.

[4] After graduating at the top of his class at Carnegie High School, Duff attended Princeton University in New Jersey, where he received a Bachelor of Arts degree in 1904.

[4] Duff was appointed Attorney General of Pennsylvania by Governor Edward Martin in 1943, serving in that position until 1947.

[1] During his tenure, he worked to strengthen the state's stream pollution law despite facing strong opposition from the coal industry.

[5] He handily defeated his Democratic opponent, former President pro tempore of the State Senate John Rice, by more than 557,000 votes.

After losing the 1956 election to Democrat Joe Clark in one of the closest elections in Pennsylvania history, Duff retired from politics, but remained in Washington, D.C., as a partner in the law firm of Davies, Richberg, Tydings, Landa & Duff.