[6] Knopp was elected to the Kenai Peninsula Borough Assembly in Alaska in 2006, serving until 2012 (including two years as assembly president), when he retired in order to unsuccessfully run for the state house.

[10] In December 2018, Knopp left the Republican caucus in the House of Representatives to push for a bipartisan coalition.

[11] On May 17, 2019, he was censured by the Alaska Republican Party State Central Committee due to his role in forming a majority coalition in the House of Representatives with members of the Alaska Democratic Party.

[14] He died on July 31, 2020, when his private Piper PA-12 Super Cruiser aircraft collided with a deHavilland DHC-2 Beaver owned by High Adventure Air Charter, near Soldotna, Alaska.

[15] A National Transportation Safety Board (NTSB) investigation indicated that Knopp had hit the Beaver at the aft end of the fuselage, that he had taken off shortly after the Beaver, that his aircraft was not properly registered, and that Knopp had been denied a medical certificate in 2012 due to vision problems.