Born in Chislehurst, Kent, in 1825, Mould graduated from King's College London, in 1842. For two years thereafter, he studied the Alhambra in Spain under Owen Jones, with whom he later co-designed the "Turkish Chamber" of Buckingham Palace. Mould's subsequent designs were often influenced by his appreciation of the Moorish style of architecture.
In 1850, Mould contributed designs for the The Great Exhibition in London and the Crystal Palace Exhibition in Manhattan, both of which were held the following year. Invited by Moses H. Grinnell to New York City in 1853 to design and build All Soul's Church, he was brought in on early plans for a great urban park in the center of the island city. Working closely with creators Calvert Vaux and Frederick Law Olmsted, he went on to design many of Central Park's notable landmarks, including bridges, bandstands, Belvedere Castle and Bethesda Terrace.
Mould was hired fulltime as an assistant city architect in 1857, and was appointed Chief Architect of Public Works in 1870. His final design was a temporary tomb for President Ulysses S. Grant in Riverside Park, replaced over a decade later by the permanent monument known as Grant's Tomb. His designs for Manhattan's Morningside Park, a revision of an earlier Olmsted-Vaux proposal, were adopted in 1881, though the park itself would not be completed during Mould's lifetime. He continued to contribute to the ongoing design and construction of Central Park until his death in New York City on June 14, 1886.
Mold also collaborated with Vaux on the design of the original Metropolitan Museum of Art and the American Museum of Natural History. Mold would also design the fountain at City Hall Park (1871), and the Morningside Park Promenade (1883) in New York City.
Besides being an accomplished architect and designer, Jacob Wrey Mould was an avid pianist and organist, and employed his talent for language in translating numerous foreign opera librettos into English.