The Tiffany glass window in the Cathedral was designed by Edward Sperry and installed about 1905.
More than that one, however, I'm enamoured of the two 1930s-era windows in St. George's Chapel ( a small and surprisingly tall room, located on the east side of the main entrance to the Cathedral, with a dramatic and rather unexpected spiral staircase ), which were designed by Peter Haworth, who ran the art department at Central Tech. Can't find any images of the entire windows online - just details - but well worth a look:
Peter Haworth, R.C.A. O.S.A. was born in Lancaster, England, on February 28, 1889. He studied at the Accrington School of Art and then, on scholarship, at the Manchester School of Art. In 1914 he enrolled at the Royal College of Art in London. He served in World War I from 1915-1918 and earned the Distinguished Flying Cross. In 1918, he returned to the Royal College of Art graduating with his A.R.C.A. He studied under Anning Bell, a noted designer of stained glass and was influenced by Burne-Jones and William Morris.
He came to Canada in 1923 and accepted a job as teacher at the Central Technical School in Toronto, becoming director of the art department in 1928. In 1939 he was appointed instructor in Design and Drawing at the University of Toronto.
He was accepted as a respected watercolour painter, but his major contribution seems to be in stained glass, in which he had begun working very early in his career. During the 1920's and 1930's he produced stained-glass windows for more than sixty churches and schools in Ontario, Quebec and Alberta. The manufacture of his windows was always carried out by the firm of Pringle and London of Toronto, but always under his close supervision. He personally selected stained glass in England or the United States. Most of the glass for his major works came from Alesburg, England, famed for the depth of colour and rich texture of its product. Generally, the more texture in a piece of stained glass, the better it will reflect the light and Haworth selected each piece of glass for each given area of design.
In 1952, Melwyn Breem of the Toronto 'Saturday Night' described Haworth's studio as follows; "We found Mr. Haworth in his study surrounded by the tools and materials of his work - samples of stained glass, stacks of exquisite, jewel like and meticulously painted sketches, and huge 'cartoons' which are the blueprints for a finished window... – steps in the designs he has done for many churches in Toronto, Montreal, Ottawa ... and elsewhere. ... (He and his assistant)... first make a ... sketch of the finished window. ... The sketch is then redrawn ... to actual scale as a 'cartoon’. The cartoon is then taken to the firm that does the actual glass making and assembling and, under Haworth's supervision, the glass sections in the design are keyed to show the colour and shape of the piece to be used. ... Templates are cut out and used as patterns for the glass. These are then cut with diamond cutters. After this comes the etching and painting of the detail. Then it is ready to be assembled and 'leaded'. The leading itself may be half an inch, a quarter of an inch or three-eighths of an inch thick, depending on the size and weight of the window. The leads are simply strips of the metal, flanged in the middle to separate adjacent pieces of glass, which are then cemented in. Then comes the actual installation of the window."
Here's an example of Haworth's work in the Montreal Museum of Fine Art's collection, showing characteristic clarity of colour ( click on the image to enlarge ):
http://www.mbam.qc.ca/au2011/en/02b.html
