Lazer was born in 1915 in Plovdiv, Bulgaria to Esther and Yitzhak. He went to Hebrew elementary school and the Municipal Gymnasium for boys. At age sixteen, he was exposed to Zionist ideology, and so he organized a Beitar cell. From 1933 to 1935, he expanded his activities across the region and directed Beitar summer camps for all of Bulgaria. In 1936, he started a Beitar program for the sake of aliyah.
After high school, he attended the University of Sofia, studying agronomy, economics and international relations. In 1936, he was appointed as senior officer within the Aliyah Bet organization. In 1938, Jabotinsky visited Bulgaria, inspiring expansion for Beitar’s activities.
In 1941, Lazer was recruited to the SIS, behind which stood IZL and British intelligence. They gathered intelligence about the German Army’s movements in Bulgaria, acquiring identification and arms. In 1942, Lazer became the commander of this network in Bulgaria. He received his orders from IZL’s Yitzhak Berman in Istanbul. In 1944, Lazer was arrested by the Bulgarian security service.
Once he was released, he fled to Istanbul, where he consulted with Berman, Eri Jabotinsky, Yosef Kellerman and British intelligence officers who wanted to draft him and send him back to Bulgaria with a paratrooper squad. However, before he could do so, he was ordered to immediately go to Cairo, and from there to the Land of Israel, to join the British intelligence service there. Upon his arrival, he made contact with Lehi through the lawyer Shlomo Alkalai. He was also summoned immediately to the Jewish Agency in Jerusalem and was immediately requested to go to Cairo. In return for going back to Bulgaria, he demanded of the British that His Majesty’s Government use its influence on Turkey to convince them to offer visas to any Jew who could make it there from Nazi-occupied territory; and that it open up the gates to the Land of Israel for the Jews of Bulgaria. However, these demands were rejected.
Lazer returned to the Land of Israel and became an active Lehi member. He was charged with recruiting police throughout the country. Gera, at one point, wanted to send him to Bulgaria to establish contact with the new government, which was Communist. However, this operation was scrapped because of the concern he might be arrested due to his previous work with British intelligence.
In May 1948, as the State was established, he enlisted in the IDF and served in the 8th Brigade, under the command of Yitzhak Sadeh, fighting in each of the brigade’s battles.
Lazer was husband to Melanie Koyumdjiksky, a father of two and a grandfather.