Nykvist was commissioned as a naval officer in the
Swedish Navy in 1991. From 1991 to 1994, Nykvist served as a command control officer on a
Västergötland-class submarine and between 1994 and 1995 he served as a navigator on a submarine of the same class. Nykvist was stationed at the
Naval Base Point Loma from 2005 to 2007 when the submarine HSwMS
Gotland was leased by the
United States Navy. There he served as Swedish liaison officer with the
United States Third Fleet and commanding officer of HMS
Gotland during the first year and as commander of the Swedish contingent in the United States during the second year. He also attended the
Salve Regina University in
Newport, Rhode Island, USA between 2013 and 2014, receiving an MA in international relations. Nykvist was then the EU Naval Force Chief of Staff during
Operation Atalanta in the
Gulf of Aden from April until September 2015 and back in Sweden he continued being the commander of the 1st Submarine Flotilla until 2016. On 4 May 2016, Nykvist was appointed
Chief of Navy From September 2020, Nykvist serves as Swedish Military Representative to the
EU and
NATO in
Brussels. In March 2022, Nykvist was appointed co-chair of the NATO Partner Interoperability Advocacy Group. Nykvist was placed as Sweden's military representative to NATO and the EU from 1 April 2023. Nykvist was appointed
Deputy Chief of the Defence Staff from 1 July 2023. ==Personal life==