The son of a judge graduated in 1914 at the Berlin College of Mines (Bergakademie). Homebound from the United States at the outbreak of World War I he was arrested by British Forces Gibraltar. On an attempt at flight Friedensburg was severely injured, resulting in a long-term stay in hospital. Not able-bodied for military service he served at the German embassy in Bern until the end of the war.
In June 1945 Friedensburg was among the founders of the Christian Democratic Union in Berlin. After the elections of October 1946 he became a deputy mayor of the city council under Otto Ostrowski and remained in that office when Louise Schroeder succeeded Ostrowski on 8 May 1947.
After the Soviet blockade of the western sectors had begun on 24 June 1948, Schroeder fell seriously ill and had to proceed to Hamburg for medical treatment. Friedensburg as her deputy from 14 August acted as mayor until on 30 November the Socialist Unity Party of Germany (SED) backed by the Soviet authorities proclaimed a separate city council of East Berlin under Friedrich Ebert Jr. and hindered Friedensburg from entering his office in Mitte. Though Schroeder officially reassumed office the next day, the elections called for 5 December could only be held in West Berlin and resulted in Ernst Reuter becoming mayor of West Berlin.
Friedensburg continued his political career as a member of the Bundestag (1952–1965) and of the European Parliament (1958–1965).
^Naimark, Norman M. The Russians In Germany: a History of the Soviet Zone of Occupation, 1945-1949. E-book, Cambridge, Mass.: Harvard University Press, 1995
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)