David Maimon was born in Rishon Le-Zion. He studied at the "M'elamah" (traditional Yemenite "Heder") under the "Mori", Rav Damari, and later studied at the Talmud Torah. During his military service he completed his matriculation exams and studied Middle Eastern history at the university. He graduated from the School of Command and General Staff and the College of National Security.
At the age of 14 he began to study mechanical metalwork (with Klotzman, the owner of the Okava factory) and at the same time he joined the "Hagana".
On the eve of the establishment of the State (1947) he took part in the underground course for squad leaders for Oriental Jews, a course which was called the "Course of the Blacks". It was Ben Gurion's idea to train army commanders as well as commander staff teachers from among the Oriental Jewish community who could serve in intelligence positions in Arab countries. When he completed the course he was enlisted to the force which defended Rishon Le-Zion and its surroundings and which went on patrols, escorted women in labor to the hospital, secured electric company workers and more. As well, he was an instructor for "Gadna" youngsters (Youth Battalion) during their training.
With the outbreak of the War of Independence (1948) he participated in several battles and when Zahal was founded he joined the "Givati" brigade. He took part in the occupation of the villages in the area and when his brother, Yaakov, fell in battle, and because two other brothers were serving in fighter units, he was transferred to "Gadna" as instructor- a position he held until 1956. In that year he transferred and served combat duties: served as Commander of the Druz reconnaissance unit, as Operations Officer of the southern general staff headquarters during the period of the "Fadayun" (Arab terrorists) attacks and as Deputy Commander in the "Golani" battalion.
Between 1965-1971 (the period of pursuit against Arabs) he was the commander of the Arava brigade. In 1971 he was commander of the Gaza Strip. During the Yom Kippur War (1973), he participated in the Sharon division and later was appointed general Governor of the Gaza Strip. In 1982 he was liaison commander of southern Lebanon, during the "Sheleg" War he was Chief of Administration of Zahal's staff and President of the Appeal Court. In 1987 he was discharged from the army in the rank of Major General and appointed Prison Commissioner.
After his release from the army he occupied himself with public and private activities: he .served as a member on the State Investigation Commission of the Suppression of Yemenite
Children; member of the directorate of the Friends of the Museum of Rishon Le-Zion; member of the Public Council of the Association for Social and Cultural Care in Natanya.