He was a member of the German Bundestag from its first election in 1949 to 1969. He was directly elected in all ballots in the Freiburg constituency. From 25 May 1960 to 1969 he was Chairman of the Bundestag Committee on Foreign Affairs.
From 16 July 1952 to 29 November 1961, Kopf was also a member of the European Parliament.
Herbst, Ludolf; Jahn, Bruno (2002). Vierhaus, Rudolf (ed.). Biographisches Handbuch der Mitglieder des Deutschen Bundestages. 1949–2002 [Biographical Handbook of the Members of the German Bundestag. 1949–2002] (in German). München: De Gruyter - De Gruyter Saur. p. 1715. ISBN978-3-11-184511-1.
Dorls (from 13 December 1950 WAV-Gast, from 17 January 1951 WAV, from 26 September 1951 Non-attached, am 23 October 1952 Mandatsaberkennung)
Frommhold (from 7 September 1949 Nationale Rechte, from 5 October 1950 Non-attached (DRP), from 26 March 1952 DP-Gast, from 11 February 1953 Non-attached)
Miessner (from 5 October 1950 FDP-Gast, from 20 December 1950 FDP)
Rößler (from 15 September 1949 Nationale Rechte, from 6 September 1950 Non-attached, from 13 December 1950 WAV-Gast, from 17 January 1951 WAV, from 26 September 1951 Non-attached, until 21 February 1952)
Thadden (from 15 September 1949 Nationale Rechte; 1950 DRP, from 20 April 1950 Non-attached)
Ott (Non-attached, from 4 May 1950 WAV-Gast, from 13 October 1950 BHE/DG, from 21 March 1952 Non-attached, from 26 March 1952 DP/DPB-Gast, from 26 June 1952 Non-attached)
Berg (from 27 June 1955, from 23 February 1956 Non-attached, from 15 March 1956 Demokratische Arbeitsgemeinschaft (DA), from 26 June 1956 FVP, from 14 March 1957 DP/FVP)
Blank (from 23 February 1956 Non-attached, from 15 March 1956 Demokratische Arbeitsgemeinschaft (DA), from 26 June 1956 FVP, from 14 March 1957 DP/FVP)
Blücher (from 23 February 1956 Non-attached, from 15 March 1956 Demokratische Arbeitsgemeinschaft (DA), from 26 June 1956 FVP, from 14 March 1957 DP/FVP)
Euler (from 23 February 1956 Non-attached, from 15 March 1956 Demokratische Arbeitsgemeinschaft (DA), from 26 June 1956 FVP, from 14 March 1957 DP/FVP)
Fassbender (from 18 November 1955 DP, from 14 March 1957 DP/FVP)
Hübner (from 23 February 1956 Non-attached, from 15 March 1956 Demokratische Arbeitsgemeinschaft (DA), from 26 June 1956 FVP, from 14 March 1957 DP/FVP)
Manteuffel (from 23 February 1956 Non-attached, from 15 March 1956 Demokratische Arbeitsgemeinschaft (DA), from 26 June 1956 FVP, from 14 March 1957 DP/FVP)
Neumayer (from 23 February 1956 Non-attached, from 15 March 1956 Demokratische Arbeitsgemeinschaft (DA), from 26 June 1956 FVP, from 14 March 1957 DP/FVP)
Preiß (from 23 February 1956 Non-attached, from 15 March 1956 Demokratische Arbeitsgemeinschaft (DA), from 26 June 1956 FVP, from 14 March 1957 DP/FVP)
Preusker (from 23 February 1956 Non-attached, from 15 March 1956 Demokratische Arbeitsgemeinschaft (DA), from 26 June 1956 FVP, from 14 March 1957 DP/FVP)
Schäfer (from 23 February 1956 Non-attached, from 15 March 1956 Demokratische Arbeitsgemeinschaft (DA), from 26 June 1956 FVP, from 14 March 1957 DP/FVP)
Schneider (from 23 February 1956 Non-attached, from 15 March 1956 Demokratische Arbeitsgemeinschaft (DA), from 26 June 1956 FVP, from 14 March 1957 DP/FVP)
Bender (from 12 July 1955 Non-attached, from 14 July 1955 Group Kraft/Oberländer, from 15 July 1955 Guest of CDU/CSU-Fraktion, from 20 March 1956 CDU/CSU)
Eckhardt (from 12 July 1955 Non-attached, from 14 July 1955 Group Kraft/Oberländer, from 15 July 1955 Guest of CDU/CSU-Fraktion, from 20 March 1956 CDU/CSU)
Finck (from 12 July 1955 Non-attached, from 14 July 1955 Group Kraft/Oberländer, from 15 July 1955 Guest of CDU/CSU-Fraktion, from 20 March 1956 CDU/CSU)
Haasler (from 12 July 1955 Non-attached, from 14 July 1955 Group Kraft/Oberländer, from 15 July 1955 Guest of CDU/CSU-Fraktion, from 20 March 1956 CDU/CSU)
Körner (from 12 July 1955 Non-attached, from 14 July 1955 FDP, from 23 February 1956 Non-attached, from 15 March 1956 Demokratische Arbeitsgemeinschaft (DA), from 26 June 1956 FVP, from 14 March 1957 DP/FVP)
Kraft (from 12 July 1955 Non-attached, from 14 July 1955 Group Kraft/Oberländer, from 15 July 1955 Guest of CDU/CSU-Fraktion, from 20 March 1956 CDU/CSU)
Oberländer (from 12 July 1955 Non-attached, from 14 July 1955 Group Kraft/Oberländer, from 15 July 1955 Guest of CDU/CSU-Fraktion, from 20 March 1956 CDU/CSU)
Samwer (from 15 October 1953, from 12 July 1955 Non-attached, from 14 July 1955 Group Kraft/Oberländer, from 15 July 1955 Guest of CDU/CSU-Fraktion, from 20 March 1956 CDU/CSU)
