Adolf Hitler was sworn in as Chancellor of Germany on January 30, 1933.
Heidegger was elected rector of the University of Freiburg on April 21, 1933, and assumed the position the following day.
On May 1, he joined the Nazi Party.

On 27 May 1933, Heidegger delivered his inaugural address, the Rektoratsrede ("The Self-assertion of the German University"), in a hall decorated with swastikas, with members of the Sturmabteilung and prominent Nazi Party officials present.

His tenure as rector was fraught with difficulties from the outset.
Some Nazi education officials viewed him as a rival, while others saw his efforts as comical.
Some of Heidegger's fellow Nazis also ridiculed his philosophical writings as gibberish.
He finally offered his resignation as rector on 23 April 1934, and it was accepted on 27 April.
Heidegger remained a member of both the academic faculty and of the Nazi Party until the end of the war.

Philosophical historian Hans Sluga wrote:
Though as rector he prevented students from displaying an anti-Semitic poster at the entrance to the university and from holding a book burning, he kept in close contact with the Nazi student leaders and clearly signaled to them his sympathy with their activism.

In 1945, Heidegger wrote of his term as rector, giving the writing to his son Hermann; it was published in 1983:
The rectorate was an attempt to see something in the movement that had come to power, beyond all its failings and crudeness, that was much more far-reaching and that could perhaps one day bring a concentration on the Germans' Western historical essence.
It will in no way be denied that at the time I believed in such possibilities and for that reason renounced the actual vocation of thinking in favor of being effective in an official capacity.
In no way will what was caused by my own inadequacy in office be played down.
But these points of view do not capture what is essential and what moved me to accept the rectorate.
Adolf Hitler was sworn in as Chancellor of Germany on January 30, 1933. Heidegger was elected rector of the University of Freiburg on April 21, 1933, and assumed the position the following day. On May 1, he joined the Nazi Party.
On 27 May 1933, Heidegger delivered his inaugural address, the Rektoratsrede ("The Self-assertion of the German University"), in a hall decorated with swastikas, with members of the Sturmabteilung and prominent Nazi Party officials present.
His tenure as rector was fraught with difficulties from the outset. Some Nazi education officials viewed him as a rival, while others saw his efforts as comical. Some of Heidegger's fellow Nazis also ridiculed his philosophical writings as gibberish. He finally offered his resignation as rector on 23 April 1934, and it was accepted on 27 April. Heidegger remained a member of both the academic faculty and of the Nazi Party until the end of the war.
Philosophical historian Hans Sluga wrote:
Though as rector he prevented students from displaying an anti-Semitic poster at the entrance to the university and from holding a book burning, he kept in close contact with the Nazi student leaders and clearly signaled to them his sympathy with their activism.
In 1945, Heidegger wrote of his term as rector, giving the writing to his son Hermann; it was published in 1983:
The rectorate was an attempt to see something in the movement that had come to power, beyond all its failings and crudeness, that was much more far-reaching and that could perhaps one day bring a concentration on the Germans' Western historical essence. It will in no way be denied that at the time I believed in such possibilities and for that reason renounced the actual vocation of thinking in favor of being effective in an official capacity. In no way will what was caused by my own inadequacy in office be played down. But these points of view do not capture what is essential and what moved me to accept the rectorate.
Martin Heidegger