An extraordinary life ended quietly in a dacha on the outskirts of Moscow last week. His rank, a major general in the Soviet army, would have given little clue to the events he witnessed, nor would the mementoes laid out in a glass cabinet in his study - a pebble painted with the inscription "To Tom: Greetings from Sochi", or a 1930s portable phonograph - until it was realised who they were from.

The childhood of Artyom Fedorovich Sergeyev, who has died aged 86, was established by decree. His father Fyodor Sergeyev was a Bolshevik whose grave can be found by the Kremlin walls, the highest honour for a fallen comrade. A party and trade union leader, he met Lenin in 1906 in Stockholm. After escaping from prison in Siberia in 1910, he arrived in Brisbane and helped found the Australian socialist party. But Fyodor was no romantic revolutionary.

Lenin's decline in health in 1920 advanced Trotsky's cause. Fyodor become one of Stalin's closest allies in the ideological battle against him and was promoted to head the Moscow Communist party organisation. A year later he invited foreign dignatories on a test run of a locomotive powered by an aircraft engine. It was never proved who put the stones on the track that derailed the engine and led to Fyodor's death, but Felix Dzerzhinsky, head of the Cheka, told his widow he suspected Trotsky supporters. Lenin assembled the politburo, entrusting Stalin to look after Fyodor's widow and to bring up his son "as a communist". Artyom Sergeyev became Stalin's adopted son.

He later described the atmosphere inside Stalin's modest dacha as "hardworking". In conversations and notes recorded in his last years, Artyom said: "It was not in any way a privilege to be close to Stalin's family. We all knew there would be war soon, and Stalin wanted us to prepare to defend our country. Most of the children of CP leaders either joined the army or went to work in the defence industry."

He painted a child's portrait of events inside Stalin's household, referring to Nadezhda Alliluyeva, Stalin's second wife, as Vassily's mum. "Vassily was Stalin's second son, and we were of the same age. He was a very good friend, he was very devoted to his friends and he had a generous heart. His father was quite harsh with him at times when he had problems at school. [Stalin's daughter] Svetlana or myself were put forward as an example. This wounded him.

"He was a good sportsman, superb horseman and brave soldier. When his half-brother Yakov was captured by the enemy, the military command restricted his flights (he was a military pilot) for fear that Stalin would lose his second son. Vassily wanted to fight, he was brave and not prepared for this 'privilege'."

In 1932 Nadezhda was found dead with a pistol next to her - "a tragedy", according to Artyom. Vassily took the leather holster from his dead mother's side, hid it, and then gave it to Artyom, saying: "Keep it as memory, or it will disappear." It is still in the glass cabinet.

The young boy remembered his conversations with Stalin: "Once he asked Vassily and myself who we wanted to be when we grew up. Vassily said we shall become officers and go to the capitalist countries to help the proletariat to break free from the bourgeoisie. Stalin replied to this: 'Are you sure you will be welcome? First, make it attractive here in the USSR, so that all the world appreciates how we live. Then, probably, you will be asked for help. But you will surely have to fight for our motherland. We have many enemies'."

Stalin is presented as a bookish, avuncular figure. He was concerned that his charge understood Russian literature, essential reading, he felt, for becoming a soldier. "Stalin often went to the theatre. He sent both of us to see The Days of the Turbins, a play by Mikhail Bulgakov which he liked very much. Once he said: "I think Bulgakov understands the Russian people like few others do, and he understands what being a leader in our country means."

In 1938, aged 17, Artyom started his military career in the artillery. Two months after the German attack in June 1941, his mother received a letter from his regiment saying he had died behind German lines. When he learned of the letter, he knew he would not be killed: "It's a Russian omen."

He led a partisan group for two months behind German lines and during the next four years escaped capture twice. He was bayoneted in the liver. A dum-dum bullet all but severed his right hand and he brought it back from the front in a bucket of snow. The leading Soviet surgeon of the era sewed it back on again, without anaesthetic.

"After the Moscow battle of September 1941 to January 1942, I thought the worst was over. But in July next year at Stalingrad it was worse. And we lost most of our comrades."

Artyom received many decorations but was proudest of the Alexander Nevsky award he got after Stalingrad. "We military knew that Nevsky, a military hero and a great statesman of the 13th century, was venerated as a saint by the Russian orthodox church, and we sacredly believed in our victory and in the country leadership.

"We won a war that according to formal criteria we should have lost. Most of our soldiers had an education that amounted to less than seven years at school. Many were of peasant descent. The Nazis had a two-year combat experience in Europe. Their soldiers were better educated than ours, and their technical equipment was far more sophisticated, especially the communications. Their attack was backed by their allies, while we only received lend-lease help during the first three years. But the Soviet army wiped out eight of every 10 German soldiers killed in the war."

By the age of 23, Artyom was a lieutenant colonel. In 1960, he was given charge of air defences around the factories in Dnepropetrovsk, eastern Ukraine, where the Soviet long-range nuclear missiles were being built. "I knew that several hundred [US] B-52 and B-47 bombers were appointed on this zone to destroy the heart of our strategic missile power. And it is due in great measure to our air defence that they never dared to attack us in the early 1960s. Their losses in bombers would be unacceptable for the American air command. This was our contribution to the building of the future nuclear parity for which 200 heavy nuclear missiles, built in Uzmash between 1963 and 1965, were decisive."

In common with many of his generation, Artyom had one word for the perestroika-era politicians, Gorbachev and Yeltsin: "Traitors." He remained an admirer of Stalin to his death.

As he lay on his deathbed, a group of war veterans brought him a medal in commemoration of Stalin. He sat up slowly as they pinned it on his pyjamas and said proudly: "I serve the Soviet Union." Those were his last words.

He leaves two sons and a daughter.

· Artyom Fedorovich Sergeyev, soldier, born March 5 1921; died January 15 2008