Jacobson's parent's where Finnish immigrants from Lapua, Ostrobotnia. Jacobso was born in Covington, Michigan and was working as a high school teacher in Northville when, in the fall of 1932, he was recruited to work for the Soviet Military Intelligence by the Comintern agent "Mrs. Morton", a pseudonym of Aino Kuusinen, the wife of the Finnish communist leader Otto Wille Kuusinen.
He traveled to, with his wife Sally, New York where the fledgling GRU agent Whittaker Chambers was assigned the task of meeting Jacobson and making a fitness report. Chambers advised against Jacobson's use as an underground agent because of his truculent temperament and the fact that he was missing fingers on one hand.
The Finnish police uncovered the group after a suspected Army Officer Vilho Pentikäinen fled to the Soviet Union with military secrets. Jacobson was arrested in October 1933, along with his Sally wife, and he promptly confessed to his role as an agent and revealed the existence of another Soviet apparatus working in Paris which included Lydia Stahl and Robert Gordon Switz.
- Chambers, Whittaker (1952). Witness. Random House. ISBN 0-89526-571-0.
- John Earl Haynes and Harvey Klehr, Venona: Decoding Soviet Espionage in America, Yale University Press (1999), pgs. 375, 469.
- Aino Kuusinen, The Rings of Destiny: Inside Soviet Russia from Lenin to Brezhnev, Morrow, 1974.
- Allen Weinstein, Perjury: The Hiss–Chambers Case, New York: Random House, (1997), pg. 106