In 1904, Holm became licentiate in philosophy (PhL) at Uppsala University, and earned his PhD in 1908. From 1906 to 1908 he studied at the University of Göttingen in Germany. In 1908 to 1909 he was a lecturer in Stockholm. Between 1909 and 1919 he worked as a physicist for Siemens & Halske in Berlin. In 1919 to 1921 he was a physicist and teacher at the Telegraphic Education Center in Stockholm, and between 1921 and 1927 associate professor at the Technical High School in Örebro. Between 1927 and 1945 he worked again for Siemens & Halske. From 1947 he was a consulting physicist at Stackpole Carbon Company in St. Marys, Pennsylvania, USA.
Holm's research area included the study of electrical discharges, but his main focus was on electrical contacts, where he was a world-leading authority. His book Electric Contacts, originally published in 1946, is still used as a standard work in the field (in its fourth edition of 1967).
In 1971, the year after Holm's death, the IEEE established the Ragnar Holm Scientific Achievement Award ("Ragnar Holm Award") for efforts in the field of electrical contacts. The prize has been awarded annually since 1972.
Since 1999, the Swedish Royal Institute of Technology (KTH) has distributed the Ragnar Holm plaque to a young physicist at the beginning of the research career, after assessing dissertations and articles in physics, primarily related to Holm's previous research on electrical contacts. Every second year, the plaque is awarded to a Swedish recipient, and every two years the selection is international.
- Holm, Ragnar (1969). "Vem är det".
- Holm, Ragnar (1908-05-25). Experimentelle Untersuchungen über die geschichtete positive Glimmlichtsäule, insbesondere über das Schichtenpotential in H2, N2, He (Dissertation) (in German). Berlin: Uppsala University. LIBRIS 1614279. Retrieved 2018-05-28.
- Holm, Ragnar (1946). Electrical Contacts. Almqvist & Wiksells akademiska handböcker. Stockholm: H. Gerber. ISBN 99-0500073-9. LIBRIS 784088.
- Holm, Ragnar; Holm, Else (1958). Electric Contacts Handbook (3rd completely rewritten ed.). Berlin / Göttingen / Heidelberg, Germany: Springer-Verlag. ISBN 978-3-66223790-8. (NB. A rewrite and translation of the earlier "Die technische Physik der elektrischen Kontakte" (1941) in German language, which is available as reprint under ISBN 978-3-662-42222-9.)
- Holm, Ragnar; Holm, Else (1979) . Williamson, J. B. P. (ed.). Electric Contacts: Theory and Application (reprint of 4th revised ed.). Berlin: Springer Science & Business Media. ISBN 3-540-03875-2. ISBN 978-3-540-03875-7. LIBRIS 5362583. (NB. A rewrite of the earlier "Electric Contacts Handbook".)
- "Holm-samlingen" [The Holm Collection] (in Swedish). Library of the Royal Institute of Technology (KTHB). 2010-06-05. Archived from the original on 2010-02-12. Retrieved 2018-05-28.
- "The IEEE Holm Conference on Electrical Contact - Ragnar Holm Scientific Achievement Award". IEEE - Components, Packaging, and Manufacturing Technology Society (CPMT). 2010-06-05. Archived from the original on 2018-05-28. Retrieved 2018-05-28.