During the trial prosecutors brought forward video evidence that showed the man raping his daughter with his fingers or other objects, while she screamed continuously.
The young girl was also tied up and gagged during the horrific crime, which the man committed with a 47-year-old co-defendant. He broadcast live video footage of the crimes onto the internet, as well as photos.
In the background, loud music could be heard that was meant to block out the child's screaming. And after the crime, the man carefully cleared up the scene to avoid being detected.
The public was blocked from entering the courtroom as the graphic video evidence was shown, with the judge saying that even experienced jurists found the trial particularly traumatic.
The father was sentenced to ten years and nine months in jail. But he will have to spend at least half of that time in psychiatric care and will only be released if he is then deemed to no longer pose a threat to the public, the presiding judge said.
The 47-year-old co-defendant was sentenced to ten years' jail.
Police were alerted to the crimes by an online acquaintance of the man, to whom he sent photos of the rape accompanied by the text “I like it when she suffers.”
The young girl is currently living with her mother at the home of her grandparents in Schleswig-Holstein.
The family's lawyer, Franziska Hammer, said that the mother knew nothing of the crimes.
“He very carefully eradicated all proof,” she said.
The family was “doing amazing things to protect and stabilize mother and child,” she added.
“There is still hope that the child will learn to trust people again and will develop into a happy, normal child.”
Police are still investigating around 50 men who are alleged to have watched the crime via a live internet stream.