He volunteered for conscription in 1993 after graduating a high school in Noarootsi, and started his service in the Single Infantry Company in Pärnu. After graduating the junior NCO school, he was appointed as a Squad Leader. In 1994, he continued his studies in the Swedish Military Academy Infantry School in Linköping and was commissioned in 1996 upon graduation as a 2nd Lieutenant. He continued his career in the Single Infantry Battalion in Pärnu where he served as a Platoon Leader and Company Commander until he went to the Swedish Military Academy Junior Staff Officer Course in Skövde. After graduation he continued his service in his former unit as Chief of junior NCO training and as Chief of Staff of the battalion. In 2002, he was deployed to Kosovo and after his deployment he attended the Senior Staff Officer Course at the Swedish Military Academy. In 2004, he was appointed as Chief of Staff of the Scouts Battalion in Paldiski and was deployed to Afghanistan as National Contingent Commander in 2006. After his deployment in 2007, he attended the Advanced Command Program at the Swedish Military Academy after which he was appointed the Commanding Officer of the Scouts Battalion. Between 2013 and 2015, he served as the Military Advisor to the Commander of the Estonian Defence Forces, General Riho Terras. He graduated from the U.S. Army War College in Carlisle, Pennsylvania in 2016 and served until 2018 as deputy director of the defence planning department of the Estonian MoD. Between 2018 and 2021, Brigadier General Karus was the Commanding Officer of the 1st Estonian Infantry Brigade.

He is the proud father of two daughters. He is fluent in Swedish and English and can communicate in German and Russian.

BG Karus takes keen interest in military history and speed skating.

Ranks:
Brigadier General 2022
Colonel 2017
Lieutenant Colonel 2010
Major 2005
Captain 2000