Sven Rosén was the son of an engineer. He earned the qualification for university in 1907 and completed his officer’s exam two years later. Rosén was a member of the Swedish team that won gold in the Swedish system team event at the Stockholm Olympics. He then graduated from the Gymnastic Central Institute with the gymnastics director’s exam in 1916. In parallel, he started his military career as second lieutenant of the First Life Grenadier Regiment in 1909 and was promoted to lieutenant in 1913 and eventually to captain in 1924. Starting in 1921, he was a gymnastics teacher at the Technical Gymnasium in Örebro. He was later appointed Knight of the Swedish Order of the Sword. Rosén married Nanne Charlotte Sundin in 1914. They had two sons and one daughter.