Hoprekstad was born in Vik, Nordre Bergenhus as the son of farmer Ragnvald Olsen Hopperstad and Ragnhild Eriksdotter Hønsi.

His play Friarar was staged later in 1913, Eli Sjo in 1916, Bjørgedal in 1919, Straumen in 1922, Trollebotn in 1925, Veslelorden in 1931, and Berstein på Strondi in 1940.

During the Occupation of Norway by Nazi Germany he was involved in the teachers' development of a strong attitude against nazification of schools.

He wrote books about the history of education in Bergen, and was principal editor of the three volumes Bygdabok for Vik i Sogn.

He was a proponent for Nynorsk language, and a board member of the society Noregs Mållag for many years.