He was drafted 15th overall in the 2017 NHL Entry Draft by the Vegas Golden Knights and agreed to a three-year, entry-level contract with the Knights on 16 July 2017. He played the 2017–18 season with the HV71 organization. Brännström earned his first NHL recall on 5 May 2018 to help the Knights during their 2018 Stanley Cup playoffs run, but did not appear in any games.
