Son of noted American author Walter O'Meara and Esther (née Arnold) O'Meara, Donn's mixed, Irish and Ashkenazi Jewish heritage would prove a formative aspect of his life. O'Meara grew up in Minnesota and then lived in New York City as a teen.
His most well known book, was published in 1972. By the mid-1940s O'Meara had become fluent in several languages, eventually learning Spanish, French, Portuguese, Catalan, Italian, German, Japanese and Hebrew. While attending Bard College, O'Meara recognized that he was Jewish due to being born of a Jewish mother.
He spent the summer of 1942 in Williamsburg, Brooklyn. He arrived back at school in the fall able to speak Galitzianer Yiddish. Prior to being drafted into World War II, O'Meara married a woman from Nicaragua named Cecilia Pereira.
During the war worked in London, England for the OSS. O'Meara and Cecilia returned to Bard College after the war. Professional O'Meara supported himself primarily through work in the advertising and public relations field in Caracas, New York, Michigan and Rio de Janeiro. While in Caracas, in 1972, O'Meara wrote which was published in 1978 in New York and London.
For the book, O'Meara assumed the pseudonym, "Michael Asheri" explaining, "Who would buy a book like that by somebody named 'O'Meara'?" The book became a seminal guide to living as a religious Jew in the 1970s. It is divided into nine major sections not including the Preface, glossary and index. In 1977, the O'Mearas moved to Israel where they settled in Petah Tikva.
At that time Cecilia changed her name to "Zippora". O'Meara then began work for the Israel Military Industries Corporation until his retirement in the 1990s. Sherman credits O'Meara with giving him the nickname, "Moose" which is also the title of the autobiography.
