Sandborg graduated from the
Military Academy Karlberg in 1993 and was commissioned as an officer and appointed second lieutenant and was assigned to the Life Grenadier Brigade (
Livgrenadjärbrigaden) in
Linköping. He served there until the brigade was disbanded on 31 December 1997. From 1998 he served in the Life Guards Brigade (
Livgardesbrigaden), where he was promoted to captain the same year. In the mid-2000s, he served as a major and commander of the
Life company in the
Life Guards in
Kungsängen. In 2009, Sandborg graduated with a master's degree from
Forsvarets stabsskole in
Oslo, Norway where he enrolled as a foreign exchange student two years prior. Later in his career, he was deputy commander of the Life Guards and has also held various positions at the
Swedish Armed Forces Headquarters in
Stockholm. On 16 November 2015, Sandborg took over as commander of the 2nd Brigade (
Andra brigaden) and also as deputy commander of the
Skaraborg Regiment in
Skövde (with appointment no later than 30 September 2019). From 1 January 2018, Sandborg was head of the Home Guard Department (
Rikshemvärnsavdelningen) at the Swedish Armed Forces Headquarters (with appointment no later than 31 July 2018). In the summer of 2018, Sandborg was promoted to major general and appointed
Chief of Home Guard and on 1 September 2018, he succeeded Major General
Roland Ekenberg to the post. He in turn was succeeded by Major General
Laura Swaan Wrede on 1 October 2022. Sandborg was made available to the
Chief of Armed Forces Training & Procurement, Lieutenant General
Johan Svensson from 1 October until 31 December 2022. Sandborg was appointed as head of the Support Unit at the
Defence Staff effective 1 January 2023. On 1 November 2025, Sandborg took office as the
Deputy Chief of Joint Operations. Sandborg has been a member of the Swedish Armed Forces Board of Tradition (
Försvarets traditionsnämnd), a unit within the National Swedish Museums of Military History (
Statens försvarshistoriska museer), which handles issues of tradition within the
Swedish Armed Forces. ==Personal life==