Lenz joined the Nazi Party in 1933, and was drafted into the Wehrmacht, whereupon he worked in the Abwehr as an intelligence agent.

In this position he rose to the rank of Leutnant and was awarded the Iron Cross twice, but sustained a lifelong injury in Poland.

He was then elected to the Bundestag in 1953, staying there until 1967 when he left due to health reasons and was succeeded by Gustav Freiherr von Gemmingen-Hornberg.

During his time as minister, he primarily worked on organizing the departments within the ministry after Franz Josef Strauss annexed part of it.

He resigned in 1962 due to the Spiegel affair, but a few months later was appointed Federal Minister for Scientific Research.

West Germany took a leading part in European Launcher Development Organisation (ELDO) during his term and he secured an agreement with NASA to launch German satellites into space in 1968.

[8][9] While studying, he met many leaders of the German Democratic Party, including Erich Koch-Weser and Theodor Heuss, which inspired him to join the student union.

[17] That same year he was elected deputy chairman of the party in Württemberg-Hohenzollern, which he did until 1952, and sat on the Trossingen municipal council.

[15] Lenz won a seat to the Bundestag in the 1953 West German federal election, representing the FDP via state list.

[28] He was replaced by Gustav Freiherr von Gemmingen-Hornberg, as he was the next candidate on the state list in accordance with the Federal Elections Act.

[29] Lenz was appointed Federal Minister of the Treasury in Konrad Adenauer's fourth cabinet on 14 December 1961.

[31] He agreed to take over the treasury as long as the condition was met that he could also be President of the Working Group of Folk Music Associations.

[45] In 1965 Lenz announced that the government had reached an agreement with NASA in which the Americans would launch a German research satellite into space.

[49] For his entire life since the injury in Poland he had he suffered from severe osteoarthritis,[8] and had great difficulty walking which required crutches.

[52] Since 2006 the Deutsche Stiftung Musikleben has awarded a medal in his honour to individuals or institutions who have made "a special contribution to anchoring music in society and the importance of amateur music-making".