Early military career Linder became a second lieutenant in the
Life Guards of Horse in 1889. He attended the
Swedish Infantry Gunnery School in 1893 and the in
Hanover, Germany from 1893 to 1895. He attended the
Royal Swedish Army Staff College from 1900 to 1902 and served as a
General Staff aspirant from 1903 to 1905. He later participated in the
Tampere operation, liberating
Pori and
Rauma and occupying the entire Pori railway line. Subsequently, he became commander of the
Savo Group, taking
Kotka and
Hamina. After the fall of
Tampere, Linder was promoted to Finnish major general. He remained in the Finnish Army until 1920 and served as inspector to the
Regent of Finland in 1919. He was master of the
Stockholm Cross Country Riding Club from 1896 to 1900, secretary of the from 1905 to 1907, member from 1908 and vice chairman from 1933 to 1943. He was an honorary member of the Stockholm Cross Country Riding Club (from 1918), the Stockholm Racing Society (
Stockholms kapplöpningssällskap) (member from 1915, vice chairman 1931-33, honorary member from 1930), the Finnish Equestrian Federation, and the
Danish Astronautical Society, among others.
Civil aviation contributions During his time as a military attaché, Linder recognized the future importance of aviation for transportation and warfare. He established the first Swedish aviation prize in 1910 (for the Öresund flight). He was a co-founder and long-term chairman of
AB Aerotransport (ABA). He also initiated and led the Nordic Finland Week in Stockholm in 1925 and served as chairman of the Sweden-Finland Society (
Samfundet Sverige-Finland) from 1920 to 1943.
Winter War (1939–1940) At the outbreak of the
Winter War in 1939, Linder, who had been promoted to Finnish lieutenant general in 1938, resigned from the
Swedish Army reserve and entered active Finnish service as commander of the
Swedish Volunteer Corps in northern Finland. His headquarters were first in
Tornio and later in
Rovaniemi. At the end of February 1940, he became commander of the
Lapland Operational Area, covering northern Finland above
Oulu. After the end of the war, he was appointed Finnish general of cavalry.
Publications Linder authored detailed accounts of the
Finnish Civil War and the Winter War, which are valuable historical sources due to their thorough documentation: ''From Finland's Freedom War
(1920), After Sixteen Years: A Retrospective on My Participation in Finland's Freedom War
(1935), On Finland’s Second Freedom War
(brochure, 1942). He also wrote on equestrian and military topics, including: Study Trips to Foreign Riding Schools 1913
(1920) and On the Cavalry: Some War Experiences'' (1930). Additionally, he published numerous articles on military, equestrian, and political subjects, especially regarding Finland and
Finland–Sweden relations. ==Personal life==