After the expulsion of his family from the Sudetenland, Riedl completed his Abitur in Münchberg in Upper Franconia in 1952 and subsequently became an inspector for the German Federal Post Office. Until 1959, he worked as a Post-Inspector at the Postscheckamt in Nuremberg. Riedl studied business administration alongside his work, and was subsequently taken over to the higher postal service. In 1962, he earned his doctorate. At the University of Erlangen-Nuremberg, he worked on banking supervision in the transport industry, especially in Germany. In 1965 Riedl became political spokesman of the Federal Ministry for Post and Telecommunications under Richard Stücklen. Stücklen, who held the office from 1957 to 1966, became chairman of the CSU group in January 1967; Riedl was, from 1966 to 1969, Stücklen's personal spokesman.
Due to the suspicion of the advantage with tax collectors around Karlheinz Schreiber in 1996, his immunity as a Bundestag deputy was lifted; the Augsburg public prosecutor ordered his house to be searched. On 14 November 1997, the Bundestag restored his immunity after the investigation by the Augsburg prosecutors failed. Later, the prosecutors office in Augsburg had to cease the investigation against Riedl in accordance with § 170 Abs.2 of the Strafgesetzbuch for nolle prosequi. In 2009, author published a book entitled Macht und Missbrauch Von Strauß bis Seehofer - Ein Insider packt aus, which alleged that on 29 October 1996, the Chief Prosecutor informed the Attorney General that the investigating prosecutor would cease the proceedings against Riedl. The Bavarian Minister of Justice at that time,, forbade the competent prosecutor to stop the investigations. By November 1997, the Bundestag restored Riedl's immunity beyond all factional borders. After the Bundestag elections in 1998, Riedl was no longer a member of parliament and therefore had no immunity, and the investigation against him was reopened and kept open until March 2000, though there was no new evidence or any investigations against him.
Business activities
From 1974 to 1981, he was the president of the football club TSV 1860 Munich and led the club temporarily back into the Bundesliga; he is regarded as partly responsible for a license withdrawal in summer 1982, which resulted in the forcible demotion of the team to the Bayernliga. Riedl later became a government consultant in Angola. From June 2014 to his death, he was the first chairman of the German-Angolan Economic Initiative.
