Born in Forshalla near Gothenburg the son of the chemist and oceanographer Otto Pettersson.
Studied Sciences at Uppsala University, graduating in 1909.
He then studied atomic physics as a postgraduate at the Institute for Radium Research, Vienna.
1913 he joined the staff of the Swedish Hydrographic-Biological Commission.
1914 he began lecturing in Oceanography at University of Gothenburg.
He became the first full professor of oceanography in Sweden and in 1938 founded the Institute of Oceanography in Gothenburg remaining as its head until 1956. He also was the head of the Bornö Hydrographic Field Station on Stora Bornö.
In 1956, aged 68, he became Professor of Geophysics at the University of Hawaii.
He wrote many popular scientific texts which helped disseminate progress in oceanography to the general audience.
In July 1947, the Albatross expedition started its around the world voyage with Pettersson as leader of the expedition.
He died in Gothenburg on 25 January 1966.