Rintelen was the son of a well-known lawyer and studied law at University of Graz from 1894 to 1898, at which pointed he began lecturing in civil law at the university. He would later serve as a professor at the same institute.^[1] He was also a professor at the Charles University in Prague before taking up a career in politics with the Christian Social Party.^[2] He served the party as Landeshauptmann of Styria from 1919 to 1926 and again from 1928 to 1933 and as Minister of Education in 1926 and 1932–3.^[2] He was the president of the Federal Council of Austria in 1923.^[3] Rintelen was also the founder and President of Steirer Bank although the scandal that followed the collapse of this initiative in 1926 was enough to see him lose his role as Landeshauptmann for a period.^[1]

In his role in Styria he was active in supporting the local Heimwehr leader Walter Pfrimer.^[4] He also maintained close links with another right-wing militia leader Georg Escherich.^[1] Rintelen's links to the far right made him a target for leftists and in May 1921 a group of miners in St. Lorenzen attacked Rintelen, throwing him out a window and stoning him.^[1] Rintelen hoped to use the Heimwehr and related groups as a personal army to launch his own version of the March on Rome and indeed he even tried unsuccessfully to enlist the aid of Benito Mussolini in this venture.^[1] He was sent to Rome in 1933 as Ambassador to Italy.^[2] Here, he became involved in intrigues with NSDAP leaders from Austria and Germany and worked to push Italian sentiments towards Nazism.^[5]

Despite having been a member of his government, Rintelen had become an opponent of Engelbert Dollfuss. He planned a coup d'état under the direction of Theodor Habicht, Rudolf Weydenhammer [de], and Fridolin Glass. Rintelen was considered a prospective Chancellor in 1934. The plan was to broadcast a false report that Dollfuss had transferred his power to Rintelen.^[6] Rintelen wanted to quit at the last minute but the plan went ahead, albeit it proved a failure. Dollfuss was killed, but the government managed to crush the uprising, with over 100 Nazis being killed in street-fighting across the country. After the coup failed, Rintelen tried to kill himself via a gunshot to the chest. He was seriously injured, but survived. While Rintelen was in the hospital, an Austrian Jew, Josef Kraus, donated blood to save his life.^[7]

"The Vienna papers carrying the story commented drily that 'if Dr. Rintelen had become Chancellor he would also have taken Jewish blood, but in a totally different fashion.'"^[8]

Rintelen's involvement in the July coup d'état saw him tried by a military court for high treason in 1935. However, Justice Minister Egon Berger-Waldenegg [de], the state leader of the Styrian Home Guard, instructed the public prosecutor to conduct the trial in such a way that he would be spared execution. As such, Rintelen was sentenced to life imprisonment. He was released from prison in February 1938, a month before the Anschluss, but took no further part in politics. He died in 1946.^[2]