Otto Schoenfeld was born in Leipzig, Germany, where he got acquainted with wrestling and fencing, as his father was, in his own words, "the most powerful athlete and swordsman in the German Army." His family emigrated to United States in 1885 and settled to Milwaukee, Wisconsin. In Milwaukee Schoenfeld continued his training in wrestling and fencing under Professor Robert Reuter and he became a naturalized US citizen in 1889. In the 1890s Schoenfeld worked as a physical instructor with the Young Men's Christian Association (YMCA), Woodson Ray University and Lyceum Conservatory in Memphis, Tennessee. In 1898 Schoenfeld moved to New Orleans, Louisiana, where he took up the physical instructor's position in the Southern Athletic Club, but soon moved over to the Young Men’s Gymnastics Club in the same city. As Schoenfeld worked as a physical instructor, he was not considered an amateur by the rules of the turn of 20th century, so we don't find his name at the US amateur wrestling or fencing annals and he never took part in the US championships in those events.
In 1900, Schoenfeld had a round trip to Europe and competed in many competitions there, including in many 1900 World's Fair sporting competitions. The local newspaper, the New Orleans Times-Picayune, describes his participation at the World's Fair sporting competitions (of which one part was the 1900 Olympics) as following: "It is unnecessary to review his trip to Europe and his participation in the world's championship games, wherein he won three championships pitted against the world's best athletes, and several second prizes, though in a half crippled condition. It will be recalled that the French government presented him with a magnificent bronze medallion, in tribute to his splendid swordsmanship, though he was debarred, through the unfounded pretext that his entry had arrived too late, from the sword contests. (In reality they were afraid of him.)" Colourful description, but if we look only the dry facts, his accomplishments at the World's Fair were first in the professional shot put and second in both professional high and long jumps and his only true Olympic participation came in the master's sabre tournament, where he lost in the first round. Schoenfeld probably also participated at the professional wrestling tournaments during the World's Fair, but those results have not survived to our time.
Back in the United States, Schoenfeld gained some fame as a professional wrestler, who wrestled bouts with such great turn-of-the-century professional wrestlers like Frank Gotch, Tom Jenkins and Tom Sharkey. He won several handicap bouts against Jenkins and Gotch and was always considered as a worthy opponent by them. Schoenfeld later worked as the athletic director of Young Men's Gymnastic Club in New Orleans and also operated a private academy of fencing and physical culture for young ladies.