Horace Trumbauer

On April 25, 1903, he married Sara Thomson Williams and became stepfather to her daughter, Agnes Helena Smith, from her previous marriage to iron dealer C. Comly Smith. Architectural Record published a survey of his work in 1904.

In 1906, Trumbauer hired Julian Abele, the first African-American graduate of the University of Pennsylvania Architecture Department, and promoted him to chief designer in 1909. Trumbauer's later buildings are sometimes attributed to Abele, but this is speculation. With the exception of the chapel at Duke University (1934), Abele never claimed credit for any of the firm's buildings designed during Trumbauer's lifetime.

In 1923, Trumbauer was hired by the Reading Company to design the Jenkintown Train Station. A fine example of Queen Anne revival architecture, it still stands today as the Jenkintown-Wyncote station and was added to the National Register of Historic Places in 2014. His work was also part of the architecture event in the art competition at the 1928 Summer Olympics.

The commission for the Philadelphia Museum of Art (1916–28) was shared between Trumbauer's firm and Zantzinger, Borie and Medary. Trumbauer's architect Howell Lewis Shay is credited with the building's plan and massing, although the perspective drawings appear to be in Abele's hand. When it opened in 1928, the building was criticized as being vastly overscaled and nicknamed "the great Greek garage". But, perched on Fairmount Hill and terminating the axis of the Benjamin Franklin Parkway, it is now considered to be the most magnificently situated museum in the United States.

In 1933, Trumbauer was commissioned to build an ornate Ancien-Regime French style mansion for Herbert Nathan Straus, the youngest son of Macy's founder Isidor Straus. Built in limestone with intricate carvings on the façade, the Herbert N. Straus House is now the largest private residence in Manhattan. It is currently owned by financier Jeffrey Epstein and the Jeffrey Epstein VI Foundation. The mansion exemplifies the classic but opulent style requested of industry barons of that time.

Despite tremendous success and his apparent ability to impress wealthy clients, Trumbauer suffered from overwhelming shyness and a sense of inferiority about his lack of formal education. He had a number of commissions until the Great Depression, but began to drink heavily. He died of cirrhosis of the liver in 1938, and is buried in West Laurel Hill Cemetery, Bala Cynwyd, Pennsylvania.