Matitiahu (Theodore) was born on June 1, 1911 in Warsaw, Poland. He made aliya in 1933 and graduated from the Teachers Seminary in Beit HaKerem in Jerusalem. He worked as a teacher in Haifa where he lived in the early 1940s with his wife Miryam. They did not have any children. One of his students told her Lehi commanders that her teacher expressed views that mirrored those of Lehi, and in 1943 two Lehi men paid him a visit in order to recruit him and his wife. Matitiahu was an enthusiastic activist with a broad education, unique rhetorical skills and effective powers of persuasion.
As a member of the executive of the General Zionists he ran the Zionist Youth branch in Haifa and conceived the idea of instilling into its ranks a Lehi member who could influence and locate potential candidates for the movement. Matitiahu became principal of a school in Ramatayim and left Haifa. His wife got a job running a Tel Aviv City Council children’s institution, and the couple lived inside the building. The place very soon became a helpful base for Lehi. Miryam employed half a dozen or so Lehi activists who needed to be located in the Sharon area. A covert storage place for weapons was dug in the backyard. During a trip to Jerusalem with his students Matitiahu met a Haifa Lehi member and immediately recruited him for the position of deputy manager of the Zionist Youth branch in Jerusalem. When the same person was transferred to Tel Aviv after a while, Matitiahu nominated him to the position of Tel Aviv Branch Manager of the Massada Zionist Youth.
Matitiahu lectured in the underground and educated generations of fighters but also demanded to go out on combat missions and so was put through a weapons course. In 1947 he was annexed to the newly established Theoretical Center. After the assassination of Count Bernadotte in Jerusalem in September 1948 Matitiahu was arrested and sent to Jaffa Prison. During the break-in he escaped and remained in hiding until the general amnesty in March 1949. He then became active in the electoral campaign of the Warriors Party.
Following the elections he became a physicist and specialized in nuclear research. He published several papers and went to work in a military base in Dayton, Ohio in the US, where he remained with his wife until his death in 1978.
Miryam returned to Israel with his casket and he was buried in Kibbutz Neve Eitan where many of its members were former associates and students of his in Poland.