Tingsten was commissioned as an officer in
Hälsinge Regiment (I 14) in 1878 with then rank second lieutenant. He was promoted to lieutenant in 1884 and he became lieutenant of the
General Staff in 1886 and captain of the General Staff in 1891. Tingsten became major of the General Staff in 1897 and lieutenant colonel in 1901 after he served 1898-99 as major in
Svea Life Guards (I 1). Tingsten had advanced within the General Staff where he belonged to the core group, which in the last decades of 1800s, seemed for the army's raise from decay and particularly for the implementation of
conscription. Important was his work as a teacher of tactics at the
Royal Military Academy in 1884, and well into the 1900s the cadets studied his seminal textbook on the subject. Tingsten was chief of staff of the 5th Army Division in 1895 and captain of
Södermanland Regiment (I 10) in 1896. In the years 1891-1900 he was first teacher at the
Royal Swedish Army Staff College and 1900-02 he was head of department at the Military Statistics Department before returning to the Royal Swedish Army Staff College as its head 1902-04. In 1904 he became a colonel and commander of
Norrbotten Regiment (I 19). Early on, he was also used in work of defense policy and for this he was hired in the
Riksdag committees appointed both in 1892 and 1901 as well as in numerous military committees. As such, he came in the opportunity to establish relationships with several prominent politicians, which undoubtedly contributed to that he in August 1905 succeeded
Otto Virgin as
Minister for War and head of the
Ministry of Land Defence in
Christian Lundeberg's coalition government. At his departure (7 November the same year) Tingsten remained in the same office in
Karl Staaff first cabinet. On 16 May 1906 Tingsten filed along with Foreign Minister
Eric Trolle his resignation, which is widely considered to be because of dissatisfaction with the speech that Prime Minister Karl Staaff held the previous day in
Andra kammaren when dealing with
suffrage. The ministerial crisis, which was triggered hereof, obtained on 29 May 1906, that Staff's ministry was replaced with a new one, with the Director General
Arvid Lindman as Prime Minister, in which Tingsten came to remain as Minister for War. When Tingsten resigned he was succeeded by
Olof Malm. Especially during the first period of Tingsten's time as Minister for War he managed to enforce some partial improvements in the defense system, including the completion of
Boden Fortress and its commandant organization. In 1906 Tingsten was promoted to major general in the army and in 1907 he became commandant in
Boden and commandant of Boden Fortress where the spent six years. Tingsten became commander of the 2nd Army Division in 1913 and Inspector of the Infantry in 1915 where he worked tirelessly and successfully for this branch continuous improvement according to the experience of
World War I. Thus he acquired in the army's officer corps the honorary title of "General of the Infantry". As Inspector of the Infantry he published
Infantry Training Regulations (
Infanteriets utbildningsföreskrifter, 1917) and
Infantry training in drill (
Infanteriets utbildning i exercis, 1918), and he changed or published several instructions regarding the infantry and machine guns. In addition, he wrote a large number of essays in military journals, especially in journal of the
Royal Swedish Academy of War Sciences (1884-1924), mainly about infantry organization and tactics. As
Chief of the General Staff from 1919, he met a neither easy or rewarding task, due to the postwar general indifference of the Swedish defense. ==Other work==