[1] In 1941, during the Soviet occupation of Estonia, Alvre was part of the Forest Brothers (Metsavennad), a group of resistance fighters who hid in the forests of Estonia and engaged in partisan activities in the struggle against Soviet authority.
In 1943, he fled to Finland and served as a volunteer in the Finnish Navy for a year during the Finnish-Soviet Continuation War, obtaining the rank of lieutenant.
[2] After World War II, Alvre graduated in 1946 from the University of Helsinki.
In his research, Alvre focused primarily on the morphology and vocabulary of the Finnic languages.
[1][3] In 1977, Alvre married medical scientist Lea Boston (née Tiikmaa).