The newspaper “HaMishmar” was first published in July 1943 in Tel Aviv. It was founded by the “HaShomer HaZa’ir” movement, whose members were dissatisfied with the workers' first newspaper, “Davar”. The banner of the front page of every issue presented the motto of the movement: “For Zionism, socialism and the brotherhood of nations”. Its readership was mainly based on subscriptions from the members the kibbutzim of the “Kibbutz HaArtzi Hashomer HaZa’ir” and members of Mapam (the United Workers Party). The first editors of the newspaper were Mordechai Bentov, Yaakov Amit and Eliezer Peri. The literary supplement was edited by Avraham Shlonsky.
In January 1948 the United Workers Party, Mapam, was founded. This party united together “HaShomer HaZa’ir”, “Ahdut HaAvoda” and “Po’alei Zion Left”. As a result, the newspaper changed its name to “Al Hamishmar”. In 1954 the Mapam party began separating itself from pro-Soviet viewpoints. As a result a range of opinions were presented, although the newspaper's main line remained identified with the Zionist left. The newspaper became a place for starter journalists and a considerable number of young reporters began their career there. “Al Hamishmar” journalists included Leah Goldberg, Yehoshua Sobol, Eyal Megged, Tom Segev, Amnon Abramovitch, Shelly Yachimovich, Avi Benayahu, the caricaturist Shmuel Katz and many others.
The last issue of “Al Hamishmar” was published on March 31st, 1995.