[1] Gunnerud was born in the Vika neighborhood of Oslo and grew up at Drøbak in Akershus.
He early artistic talent was first discovered by sculptor Sigri Welhaven.
He attended the Norwegian National Academy of Craft and Art Industry (Statens håndverks- og kunstindustriskole) from 1947 to 1950.
This was followed by attendance at Norwegian National Academy of Fine Arts (Statens kunstakademi) from 1951 to 1954 where he was instructed by Per Palle Storm.
[2][3][4] Among his works are the tree sculpture Midgardsormen from 1973, the bronze sculpture Vettløyse from 1978 (located in Oslo), Fenrisulven vil bryte seg løs from 1980 (in Tokyo), Soltreet (suntree) in Stavanger from 1984 and Bacalhaujagt from 1996 (in Lisboa).