Dyrssen became a teacher in Sweden's strategic conditions at Royal Swedish Army Staff College in 1935, and was appointed major in 1936 and lieutenant colonel in 1938.

In his teaching as a teacher at the Royal Swedish Army Staff College, he emphasized the cohesion of Sweden and Finland in military policy terms.

He undoubtedly drew the logical consequence of his view of the affiliation of these two countries when the harbingers of the Winter War began to be discerned in the autumn of 1939.

[1] At the announcement of his death, Field Marshal Carl Gustaf Emil Mannerheim sent General Ernst Linder a telegram, in which it was stated: "Magnus Dyrssen's significant contribution to the formation of the corps, his outstanding officer qualities will always assure him one of the foremost places in the history of the Swedish Volunteer Corps.

"[2] On 9 March 1940, Dyrssen was buried in Engelbrekt Church in Stockholm by Pastor Hans Åkerhielm of the Swedish Volunteer Corps.