[1] In the mid 1950s, Hedqvist embarked upon his career as a taxonomist, describing first a new bark beetle and then what would become a very large number of Hymenoptera species and genera.
In 1959 he was employed as a research assistant position at the Swedish Museum of Natural History (NHRM, for Naturhistoriska riksmuseet), where he had the opportunity to focus more on taxonomy.
Nevertheless, he left the position in favour of employment as a field entomologist back at the Swedish Forest Research Institute in 1963.
In 1971, he moved back to the NHRM, holding a newly established position as a taxonomist with special focus on parasitoid wasps, funded by the Swedish Research Council.
Hedqvist received an honorary doctorate from Uppsala University in 1977 for his work on the taxonomy of parasitoids.