Born in Otterberg, Barvaria, on December 23, 1850, Oscar Solomon Straus immigrated with his family to Talbottom, Georgia, in 1854. He moved to New York City in 1867, where he studied at the Collinsworth Institute and Columbia College. Straus studied law and graduated from Columbia Law School in 1873. He opened his own firm, Hudson & Straus, in New York City and stayed there for eight years before retiring to work with his father and brothers at the import firm of L. Straus & Sons. He entered politics by supporting a New York City mayoral candidate; he also backed New York governor Grover Cleveland's presidential election. Cleveland appointed Straus minister to Turkey, where Straus spent two years. He returned home and called for aid to Jews in Russia, an item which President Benjamin Harrison would include in his 1889 State of the Union speech. Straus returned to Turkey as ambassador, calling for the establishment of a national Jewish homeland in Iraq.

He subsequently befriended President Theodore Roosevelt, who named Straus to the Permanent Court of Arbitration at The Hague, Netherlands; Straus served there until Roosevelt named him secretary of commerce and labor in 1906, making Straus the first Jew to hold a cabinet position. He would remain in that post for the rest of the Roosevelt administration.

Straus went back to Constantinople for a third time when President William Howard Taft made him ambassador to Turkey (1909-1910). He returned to New York, running unsuccessfully for governor on the Progressive ticket in 1912, and collaborated with former President Taft on the League to Enforce Peace, a group advocating a league of nations to prevent war. Straus died in New York City on May 3, 1926.