Enderlein competed in five races in the winter of 1961 to 1962 and finished fifth at the German Junior Championships.
She debuted at the FIL World Luge Championships 1963 in Imst, but achieved only 24th place after a fall, while her teammate Ilse Geisler won.
A few days later, Enderlein finished second behind Geisler, at the international event for the "Ehrenpreis der Stadt Innsbruck" on the newly created Bob-Rodel Igls run in Innsbruck-Igls.
Her first major win in a national competition was at the GDR Championships in Oberbärenburg in February 1963;  Helga Meusinger, who had previously won at the European Junior Championships in 1961 and 1962 finished second, while Ilse Geisler did not reach the top three because of two falls.

Enderlein debuted and won at the 1964 Winter Olympics in Innsbruck with the best time in all four heats, each on 30, 31 January and 4 February, with a 0.75 second advantage over Ilse Geisler and Austrian Helene Thurner.
She set a new record of 50.87 seconds.
During the closing ceremony on 9 February 1964, she was awarded the honour of being flag carrier for the United Team of Germany.
Enderlein defended her title at the GDR Championships in Friedrichroda on 21 to 22 February 1964 against Ilse Geisler, and defeated Geisler at the Mitropa Cup.
In June 1964, together with Thomas Köhler, who was also victorious at the Olympics, Enderlein was awarded the Patriotic Order of Merit in Silver in celebration of the Week of Youth and Sports.
The GDR politicised its athletic achievements in its fight for recognition as an independent country and for the right to field its own teams at future Olympic Games.
Following that, Enderlein was part of the delegation to the Women's Congress in Berlin from 25 to 27 June 1964.

Enderlein luged at the FIL World Luge Championships 1965 on 6 and 7 February in Davos and won her first World Championship title with an advantage of over one second after four heats, ahead of Petra Tierlich, Ilse Geisler and Barbara Winter.
A week later at the 1965 GDR Championships in Oberhof she won with a one-second advantage ahead of Petra Tierlich and Ilse Geisler, despite disqualification in the second heat – only two of the three heats were counted.
Because of her consistent achievements, Enderlein was ranked third in the vote for East German Sportswoman of the Year, behind Hannelore Suppe and Gabriele Seyfert.
The 1966 Luge Championships on the Spießbergbahn in Friedrichroda was cancelled due to föhn winds and the associated thaw; there were also no national championships that year.
Enderlein inaugurated a new open-air public bath in Raschau on 22 June 1966.

Enderlein defended her title at the FIL World Luge Championships 1967 in Hammarstrand, achieving the best time in all four heats on 18 and 19 February and achieved a position 1.39 seconds ahead of Petra Tierlich and Helene Thurner.
She also set a new luge record of 50.93 seconds.
Because of the Hallstein Doctrine, the East German lugers were not permitted to compete at the FIL European Luge Championships 1967 at Königssee.
As this was the only European Luge Championships which took place between 1963 and 1969, Enderlein never participated in any.
At the GDR Championships in Oberhof that year she finished second behind Anna-Maria Müller.
Enderlein competed in five races in the winter of 1961 to 1962 and finished fifth at the German Junior Championships. She debuted at the FIL World Luge Championships 1963 in Imst, but achieved only 24th place after a fall, while her teammate Ilse Geisler won. A few days later, Enderlein finished second behind Geisler, at the international event for the "Ehrenpreis der Stadt Innsbruck" on the newly created Bob-Rodel Igls run in Innsbruck-Igls. Her first major win in a national competition was at the GDR Championships in Oberbärenburg in February 1963;  Helga Meusinger, who had previously won at the European Junior Championships in 1961 and 1962 finished second, while Ilse Geisler did not reach the top three because of two falls.
Enderlein debuted and won at the 1964 Winter Olympics in Innsbruck with the best time in all four heats, each on 30, 31 January and 4 February, with a 0.75 second advantage over Ilse Geisler and Austrian Helene Thurner. She set a new record of 50.87 seconds. During the closing ceremony on 9 February 1964, she was awarded the honour of being flag carrier for the United Team of Germany. Enderlein defended her title at the GDR Championships in Friedrichroda on 21 to 22 February 1964 against Ilse Geisler, and defeated Geisler at the Mitropa Cup. In June 1964, together with Thomas Köhler, who was also victorious at the Olympics, Enderlein was awarded the Patriotic Order of Merit in Silver in celebration of the Week of Youth and Sports. The GDR politicised its athletic achievements in its fight for recognition as an independent country and for the right to field its own teams at future Olympic Games. Following that, Enderlein was part of the delegation to the Women's Congress in Berlin from 25 to 27 June 1964.
Enderlein luged at the FIL World Luge Championships 1965 on 6 and 7 February in Davos and won her first World Championship title with an advantage of over one second after four heats, ahead of Petra Tierlich, Ilse Geisler and Barbara Winter. A week later at the 1965 GDR Championships in Oberhof she won with a one-second advantage ahead of Petra Tierlich and Ilse Geisler, despite disqualification in the second heat – only two of the three heats were counted. Because of her consistent achievements, Enderlein was ranked third in the vote for East German Sportswoman of the Year, behind Hannelore Suppe and Gabriele Seyfert. The 1966 Luge Championships on the Spießbergbahn in Friedrichroda was cancelled due to föhn winds and the associated thaw; there were also no national championships that year. Enderlein inaugurated a new open-air public bath in Raschau on 22 June 1966.
Enderlein defended her title at the FIL World Luge Championships 1967 in Hammarstrand, achieving the best time in all four heats on 18 and 19 February and achieved a position 1.39 seconds ahead of Petra Tierlich and Helene Thurner. She also set a new luge record of 50.93 seconds. Because of the Hallstein Doctrine, the East German lugers were not permitted to compete at the FIL European Luge Championships 1967 at Königssee. As this was the only European Luge Championships which took place between 1963 and 1969, Enderlein never participated in any. At the GDR Championships in Oberhof that year she finished second behind Anna-Maria Müller.
Ortrun Enderlein