Peyron attended the
Royal Swedish Army Staff College from 1910 to 1912, was an aspirant in the
General Staff from 1913 to 1915 and was appointed captain of the General Staff 1917. He returned the same year as
ryttmästare to the Life Regiment Dragoons. Peyron, who had left the Swedish Army in 1918, took part in the
Finnish Civil War as a General Staff officer at headquarters. He participated there, among other things, to the plans of the
Tampere and the
Vyborg operations and was appointed Finnish lieutenant colonel. Back in the Swedish Army, he served as a military attaché in
Rome from 1919 to 1921, became a major in the army in 1924, was a military attaché in
Berlin from 1924 to 26 and chief of staff at the Cavalry Inspectorate (
Kavalleriinspektionen) from 1926 to 1932. He was promoted to major in the General Staff in 1926 and lieutenant colonel in 1928. During the
interwar period, Peyron sought to find ways to counteract the cavalry's downsizing. While maintaining the traditional cavalry name, the units would be composed of parts with such different marching capabilities as "cavalrymen",
bicycle troops and
motorized troops. In 1932, Peyron became lieutenant colonel in the
Life Regiment Hussars in
Skövde, was promoted to colonel in the army in 1934 and was the regiment's executive commander from 1935 to 1937, after which he was executive commander until 1940 of the
Life Regiment of Horse. In 1943, Peyron was promoted to major general and appointed Inspector of the Cavalry. In this position, Peyron sought to promote the field operations of the units. He took special interest in the tactics. During
World War II, Peyron was first commander of the cavalry brigade and then for a long time carried out operations as division commander in
Värmland. He retired from active service in 1943. Peyron was chairman of Skövde Cross Country Riding Club (
Skövde fältrittklubb) from 1933 to 1937, vice chairman of
Stockholm Cross Country Riding Club from 1937 to 1940 and a member of the Swedish Equestrian Federation (
Svenska ridsportens centralförbund) from 1937 to 1943. ==Personal life==