During the offensive, his corps was attacked by four divisions of the Soviet 32nd Army and fell back to the region south of Ilomantsi.

During his time in Germany, Mäkinen fought for the imperial German Army on the Eastern Front of World War I as a member of the 27th Royal Prussian Jäger Battalion, taking part in several battles in the regions of Misa, Gulf of Riga and Lielupe.

In 1919 he was promoted to captain and took a teaching position in the Reserve Officer Schools, followed by a taking command of a battalion from 1922 to 1923.

[3] During the Finno-Soviet Winter War of 1939–40, Mäkinen worked in the General HQ Section I (Finnish: Jaosto I), which was in charge of organization and training.

[1][5] At the beginning of the Continuation War, fought by Finland and Nazi Germany against the Soviet Union in 1941–45, Mäkinen was in charge of the Organization Department of the Finnish General HQ.

[4][6] The corps was first tasked with the containment and destruction of the reinforced Soviet 168th Rifle Division surrounded in the area of Sortavala.

In this role, he was in charge of determining how limited labor resources were to be divided between tasks such as agriculture and forestry work, military industry, and the construction of fortifications.

[4][13] During his time in the office, he was most notably responsible for the decision to grant leave to some 10,000 infantrymen for a month to reduce the shortage of agricultural labor during the fall of 1943.

[20] Parts of the corps participated in the routing and partial destruction of the 176th and 289th Rifle Divisions of the Soviet 32nd Army through encirclement in the Battle of Ilomantsi.

In early 1945, he was considered for Minister of Defence by the post-war President of Finland Carl Gustaf Emil Mannerheim, but this was blocked by the political left due to his 1941 cooperation with the Germans.

[1] He left the military in 1946, becoming the chief executive officer of Parava Oy, a Finnish limited company.

[23][24] Mäkinen was suspected of having planned the hiding of armaments and an unsanctioned mobilization and spent a year in prison.