Høyem grew up in Byneset, where his paternal grandfather and his father had important positions in school, church and music life. Olav also planned to become a teacher, completing the Klæbu seminar from 1848 to 1850. For a brief period of time he worked as a teacher and sexton in Lademoen and Lade in Trondheim, before he was assigned a post as a teacher in Kristiansund.
After two or three years, poor health forced him to give up the teaching profession. In 1858 he completed the first telegraphist course in Norway, and in 1859 he returned to Trondheim. He had a large family and lived at Ila in Trondheim for the rest of his life. He eventually was employed by Norges Bank [Bank of Norway].
Even if he had to give up his teaching career, he remained by nature a teacher all his life. Høyem eagerly endeavoured to enlighten the masses, and had many irons in the fire. He had very strong ties to his home district, Byneset, and in 1862 he published Nes eller Bynes, a description of his home district (expanded and Norwegianised edition in 1894). In 1865 he took the initiative to establish Byneset Sparebank [savings bank]. He was interested in the old medieval church at Stein, and collected funding for an organ which was installed in 1874. For a short period of time he also operated an experiential college in the district.
Olav J. Høyem was an avid fan of a separate Norwegian written language, different from the prevailing Danish, and based on the spoken language. The stiff Danish was alienating for people in general, hampering general enlightenment. Believing that Ivar Aasen's Norwegian [‘nynorsk’] had too little scope, lacking elements from central Norway and Trøndelag, Høyem developed his own form of the Norwegian language. He published his own translation of the Norwegian Constitution as well as practical textbooks on measures and weights. But the most known of his books were his translations of religious texts: Luthers katekes [Luther's catechism] (1873) and Den helige saga og kjørkjesaga (Bible history) [The holy saga and the church saga] (1882).
Høyem was active in debates on social issues, and his support of Johan Sverdrup cost him his employment at Norges Bank for a period of time.
At his burial procession from the church in Byneset in February 1899, hymns by Elias Blix were sung. This was the first time in living memory that Norwegian texts had been sung in the old church.
Recommended reading: Olav Røkke: Olav Jakobsson Høyem. Nidaros folkeskriftnemd 1930.