Eidlitz began working for his father. His first independent work was the 1877-78 reconstruction of
St. Peter's Church in the
Bronx after it was damaged by fire. It had originally been designed by his father. His early
Gothic Revival and
Romanesque Revival designs, including
Dearborn Station in Chicago,
Michigan Central Station (1887) in
Kalamazoo, and the precursor to the current
Buffalo & Erie County Public Library in
Lafayette Square, show his father's influence. His Romanesque Revival design for the Metropolitan Telephone Building on Cortlandt Street (1886) was the first purpose-built telephone building in New York City. Another Romanesque design was selected for
The Bank for Savings in the City of New-York which was erected in 1894. For the
American Society of Civil Engineers' new Society House on
220 West 57th Street (1897), he used a French Renaissance and Gothic design. By the turn of the century, Eidlitz embraced the
Beaux-Arts style. In 1903, he formed Eidlitz & McKenzie with Andrew McKenzie, who had been a construction supervisor and engineer for his father's firm. Eidlitz & McKenzie was one of the first architecture firms that put architects and engineers on equal footing. Eidlitz & McKenzie worked primarily on telephone buildings, but their best-known design was for the
New York Times Building (1903–04) for the publisher
Adolph Ochs. Their design used their expertise in connecting buildings to subterranean infrastructure. The building, the second tallest in the city at the time, incorporated the
Times Square station of the
New York City Subway into its basement levels.
Times Square was named for the building. Eidlitz's other works include the
Association of the Bar of the City of New York (1898), located at 42 West 44th Street in Manhattan, New York City. It is still occupied by its original client, unlike many other old New York City buildings. He also designed, with others, the
Bell Laboratories Building, a
National Historic Landmark in New York City, as well as the First National Bank on West Commerce Wtreet. The interior decoration design of the Arnot Memorial Chapel at
Trinity Church in
Elmira, New York is also attributed to him. ==Marriage and family==