Hannes was born in Iceland, on the Westman Islands, where he lived until the 1973 volcanic eruption. In 1974, he moved to the Faroe Islands. His MSc in physics is from Copenhagen University, and he earned his PhD from the Technical University of Denmark, optimizing T-shaped GaAs quantum wires. Also, he visited EPFL in Lausanne, Switzerland, characterizing semiconductor lasers.
After the PhD, he was an Assistant Research Professor at DTU and an R&D engineer before moving back to the Faroe Islands. First, working as a software engineer at Faroese Telecom, and then as the head of research at an Aquaculture Research institution. Since 2009, he has been a professor at the University of the Faroe Islands. He established the Software Engineering and Data Science educations while participating in various biostatistical and bioinformatics projects, including, rib deformities in rainbow trout, cod farming, primary carnitine deficiency, antibacterial resistance, a statistical model for salmon sea lice, suspicion of child maltreatment observed by dental professionals, the Atlantic herring genome, epidemiological research on COVID-19, and finally, the isolated population of the Faroe Islands.