With his international outlook, his concrete experience of the everyday life of the war and his great work capacity, Raab was one of the Swedish Army's foremost officers during the 19th century.

[2] Raab was employed as an adjutant to Carl von Mansbach, the Swedish-Norwegian minister in Berlin, and he attended the Prussian Staff College from 1855 to 1858.

[2] Initially employed at the headquarters, he participated in the battle of Dybbøl on 17 March, but was soon seconded from there and assumed command of the 1st Company of Swedish and Norwegian volunteers of captain Aaröe's corps.

Best known among the expeditions carried out by this company under Raab's leadership is the nightly operation to Loit church village in Schleswig, at which time several prisoners were taken.

[2] In 1865, Raab was promoted to captain of the Swedish Army and was appointed the same year as information officer in tactics, regulations and war articles at the Military Academy Karlberg.

From January 1866 to September 1873, he was a teacher of warfare and war history at the Higher Artillery School (Högre artilleriläroverket, later the Royal Swedish Army Staff College) in Marieberg.

In 1873 he drew up the proposal for criteria for a new, based on general conscription, fully contemporary army organization, which, after being examined by a committee, in whose work Raab was ordered to participate, was the basis for King in Council's presentation on the subject to the Riksdag of 1875.