Iakov Belson was born in 1921 in Petrograd. After graduating from high school, he was drafted for the Soviet-Finnish, or Winter War of 1939-40. Serving as a private, he received a concussion. After treatment in a military hospital, he returned to the army.
For Belson the Soviet-German war began on its first day, June 22, 1941, when he was serving near Brest, Belorussia, i.e. at a point that met the brunt of the German attack on the Soviet Union. He was a witness to and a reluctant participant in the Red Army's retreat from Belorussia in the summer of 1941. At some stage, Belson was withdrawn from active service and sent to a commanders' course. He returned to active service as a senior lieutenant and a commander of a reconnaissance battalion (in the winter it became a battalion of skiers) on one of the western fronts. In February 1943, during an operation to capture the "Orel bridgehead" (held at this time by the Wehrmacht), the command of Belson's skiers' brigade decided to use the reconnaissance battalion as an infantry brigade. In one battle, senior lieutenant Belson led his battalion in an attack that encountered strong heavy machine-gun fire. Although wounded in the leg, he continued to lead the offensive in which his battalion succeeded in advancing by 1.5 kilometers. As a result, he was awarded the Order of Alexander Nevsky.
In January 1945, during fighting in East Prussia, Belson was seriously injured and lost both of his legs. Nevertheless, he continued in army service, retiring in 1945 with the rank of major and as chief of the army's intelligence department. Upon retirement, Belson entered the Leningrad Institute of Law (since the end of 1945 – the Faculty of Law at Leningrad/St. Petersburg State University). He defended two dissertations on law and during 30 years taught as professor at the Faculty of Law and at the Law Academy of the Ministry of Internal Affairs in this city. He wrote many books on law and law enforcement in Western countries, including Great Britain and the USA, as well as on other topics. Belson urged the Soviet Union and later Russia to join Interpol. He was regarded as the top specialist in the Soviet Union on the ICPO (Interpol).