John was born on March 21, 1858 in Philadelphia, Pennsylvania, United States, the eldest child of Thomas and Margaret (Haines) Stewardson. His great-grandfather, Thomas, had emigrated from Westmoreland, England, to Philadelphia in 1789 and died in Newport, Rhod Island, in 1841.
The boy went first to private Philadelphia schools and, from 1873 to 1877, to Adams Academy at Quincy, Massachussets. He entered Harvard College with the class of 1881. At the end of two years he went to Paris and began his architectural study in the Atelier Pascal. He entered the Ecole des Beaux Arts in 1881 and remained there but one year. During these three and a half years he spent all his leisure time in traveling over France and sketching indefatigably.
Upon his return to Philadelphia in 1882 he entered the office of T. P. Chandler. Working there and in other architects' offices until 1885, he rapidly became known for his ability and charm.
During this all-too-brief association of ten years, Stewardson found time for much additional travel, which undoubtedly vivified and stimulated the firm's output. He traveled in Italy and Belgium in 1888 and in England in 1894. It was on this later trip that he became so charmed with the brickwork of St. John's College in Cambridge that the University of Pennsylvania designs, then under way in the office, were changed from stone to brick stone-trimmed - the tower of the dormitory group there bears the date 1895.
In 1897 his friends collected a fund that was given to the University of Pennsylvania to endow a traveling fellowship under the auspices of the school of architecture, the Stewardson Fellowship.
On a winter afternoon he went skating on the Schuylkill with some friends. In the late dusk he was separated from them; and there was heard the sound of breaking ice, and a cry, then silence. This accident seemed the more tragic because of his approaching marriage.
John Stewardson was one of the founders of the American Institute of Architects and president of the T-Square Club. He was one of those architects who are primarily artists. His many water colors, rich yet delicate, reveal the sensitiveness of his taste, which kept its basic romanticism from becoming sentimental or mawkish.
He had a love for people of all kinds that amounted to social genius and was attested by the many expressions of grief at his untimely death, alike from friends, office mates, and architects all over the country.
Tall and thin, he had always a passion for outdoor life of all kinds.
