William F. Senior was an active piano maker during the early to mid 19th Century. He is listed as early as 1830, with his first workshop located at 186 William Street in New York City. Senior built primarily square grand pianos, and his reputation quickly spread as being a maker of excellent instruments. In 1846, Senior went into partnership with James Grovesteen, establishing the firm of Senior & Grovesteen. Pianos were built and sold under both the names of 'Senior & Grovesteen' as well as 'Grovesteen & Senior'. Instruments by the firm were widely exhibited and won several awards for design and construction. This partnership was dissolved in 1848. That same year, Senior joined the firm of Robert & William Bennett to form the firm of Bennett, Senior & Company. Also being a short-lived partnership, this firm was dissolved within a year or so. Willaim Senior is listed as building pianos again under his own name during the 1850s while sharing a workshop with makers Francis Taylor and Joseph Rittenhaus. There is no mention of William F. Senior building pianos after about 1860.