Johannes Rauschenbach was born in Schaffhausen on 21 November 1856, the son of the machine manufacturer Johannes Rauschenbach-Vogel and Maria Barbara Vogel. His father, a shareholder in the struggling International Watch Company founded by the American F. A. Jones, bought it on 17 February 1880 for 280,000 francs, and died a year later. In 1881, aged 25, the son took over the business, which traded as the Uhrenfabrik von J. Rauschenbach. He married Bertha Rosina Schenk (1856–1932), and like his father took her name alongside his own.
He ran the factory successfully for almost a quarter of a century. With the technical director Johann Vogel, who designed IWC's calibres until 1919, and the manager Urs Haenggi, who joined in 1883, stayed 52 years, ran the factory floor, won new customers and kept outside interests from buying in "in the interest of the noble Rauschenbach family", he built up the business. In 1885 the company made the Pallweber pocket watch, an early digital display of hours and minutes under an Austrian patent, and from 1888 it brought electricity to the factory.
He had two daughters. In 1903 the elder, Emma (1882–1955), married the psychiatrist Carl Gustav Jung, who thereby became a partner in the watch factory; the same year the younger, Bertha Margaretha (1883–1932), married the Schaffhausen industrialist Ernst Jakob Homberger, director of Georg Fischer. Johannes Rauschenbach-Schenk died in Schaffhausen on 2 March 1905, aged only 49. His widow, daughters and sons-in-law inherited the company; from 1929 Homberger bought out Jung's share and became sole owner, and his son Hans Homberger ran IWC from 1955.
His birth date and his daughters' marriages come from Watch-Wiki, a German watch encyclopedia; the IWC dates are from Wikipedia.