Following the war, he was a volunteer crewman on the Aliyah Bet ship Hatikva to transport Holocaust survivors to Mandatory Palestine, and was imprisoned by the British on Cyprus before settling in Israel.
Under his directorship, the AACI flourished; Greenfield pioneered and established loan funds, a mortgage company, and a variety of housing projects in Jerusalem, Tel Aviv, and kibbutzim.
[1] In 2010 his best-known book, which he spent more than a decade researching, The Jews' Secret Fleet,[3] was published, about the participation of North American sailors in Aliyah Bet.
He founded and contributed editorially to Israel's first-ever English language magazine, FrontPage, and later a monthly titled Rossvet, aimed at Russian immigrants.
Rosenthal was inspired to create the documentary after reading Greenfield's book The Jews’ Secret Fleet, which has an introduction by Martin Gilbert.