Meshulam was born in Poland to Reuven and Bluma in 1923. His father was an intellectual who taught Hebrew in the Diaspora, and once the family made aliyah in 1927, he became an accountant in Jerusalem. Meshulam had two brothers and a sister. The house was traditional, and Meshulam was sent to study in cheder. His secular studies were disorganized and somewhat haphazard, taking place in various institutions.
When he was still a youth, during the 1936-1939 riots, after the Arabs had attacked a Jewish bus, he decided to take revenge on his own initiative and somehow acquired a grenade which he threw at an Arab bus in Lifta. When his family learned of this, his parents and grandmother were very concerned. At the beginning of World War II, he wanted to join the fight against the Nazis, but he was too young to volunteer legally. Nevertheless, he managed to lie and enlist at age sixteen, ending up first in the Transportation Corps and then in the Jewish Brigade.
While serving in the British Army, he met another solider from the Land of Israel who was a Lehi member, and he was persuaded to join as well. Afterwards, he was active in the Jerusalem underground, and after the Partition Plan was announced, he and his friend Little Yoav managed to take over a British armored vehicle, after capturing its personnel. The Hagana forced him to return the armed vehicle to the British, but not before taking the machine gun for the underground. He participated in anti-Arab battles, including the bloody battle for Notre Dame. He was also part of the Bernadotte assassination operation. Afterwards, he was smuggled to France for his own protection.
Upon his return, he joined a Communist party, but he soon became disappointed with its path. He started working as a goldsmith and coppersmith and with alpaca fleece. When the Six-Day War ended, he was the first to become business partners with an Arab storeowner by Jaffa Gate in Jerusalem’s Old City. While the store had been a laundry, he wanted to make it a store for objets d’art. He later sold his part in the business and set up a studio. Meshulam was a good friend of Yehoshua Cohen, and he helped him establish the Kfar Etzion Field School. His store and studio were a meeting place for everything associated with this. He also helped those who had recently made aliyah from South America.
In 1960, he married Batya Salomonowicz of Beit Hanan, then a student in literature and philosophy. They had a son and daughter and lived in Jerusalem.
Meshulam passed away on February 20, 1997 at age 74. He was buried on Har Menuhot, right above the spot where he seized the British armored vehicle.