[1] His father, Leon (Leopold) Loeb, was born to a Jewish family in Alsace, France, and immigrated to Los Angeles in 1853 where he opened a dry goods store.
[2] Given that Los Angeles was a small city at the time (5,000 population), he quickly met Harris Newmark, a prominent established Jewish businessman; and in 1879 married his daughter Estelle.
[8][3] Leopold Loeb served as the French Consular Agent for over fifteen years.
[3] Joseph's younger brother Edwin J. Loeb graduated from Los Angeles High School in 1904.
[1] Edwin and Joseph Loeb read proof for their grandfather, Harris Newmark, at the time of the publication of his book on Southern California.
His charitable, political, and educational activities were extensive and included: President of Hillcrest Country Club (Los Angeles):[9] 1933–1937, Board of Directors of Los Angeles County Bar Association: 1915–1922, President of United Jewish Welfare Fund: 1937; and General Campaign Chairman: 1938, Founder, Director and First President of Southern California Chapter of the Arthritis Foundation, Director of Jewish Orphans Home of Southern California (now called Vista Del Mar Child Care Service): 1916–1939; from 1920–1926 he was its President, and Board of Governors, Los Angeles Civic Light Opera Association.