Shimon was born in Yemen on May 15, 1921 to Zvia and Menahem Mizaki. In his youth, he studied in cheder. The family, consisting of six brothers and sisters, made aliyah in 1934 and settled in Tel Aviv. Shimon took evening classes in Herzliya Gymnasium. He joined the Olei Eden youth movement.
In 1939, he joined IZL. He was trained and took part in many IZL activities against German institutions in the Land of Israel, including burning German newspapers and flags. At the time of the split, he had to abandon underground activities due to medical concerns, but in 1942 he joined Lehi. Shimon was trained in firearms at Segula and assigned to provide materials for recruits in additional courses. He was putting up posters and shortly found himself in charge of a cell doing the same. At the same time, he supported himself by working for Ford. In 1945, he was sent to Raanana as a supervisor in the orchards, where Lehi’s secret press was set up. In light of this role, he had to live in a shaky structure in the orchard and to be in the field day and night. He married Sarah Berra, and she moved into the orchard with him.
Soon he was moved to the operations division, and from that day forward he participated in many operations: laying mines on the roads to attack British Army vehicles, attacking British police and soldiers walking the streets of Tel Aviv, and seizing cash and merchandise from speculators’ warehouses to finance various underground operations. He liberated two prisoners from the APC police station and participated in the operation to blow up the Jaffa CID.
After the Partition Plan, the Arabs began attacking the Yishuv. On the Jaffa-Tel Aviv border, Jews defenders set up posts, but the British would come periodically to confiscate weapons from them. Lehi set up a rapid-action based on Me’a She’arim Street in Tel Aviv, called the Hikon. Lehi men headed by Shimon were stationed there, armed twenty-four hours a day. They stopped a British armored vehicle with gunfire and caused it to retreat, and they even attacked the Arab positions from which snipers would shoot at Tel Aviv.
Later, he enlisted in the IDF with other Lehi Members and served in Battalion 89 under Blond Dov, fighting in all its battles. He was injured at Auja el-Hafir, the battle in which Dov was killed.
After the war, he worked at the engineering department of the Tel Aviv Municipality until he retired.
Sarah and Shimon had three children and numerous grandchildren.