The interior decorations by Tiffany Glass and Decorating Company and others were added in stages after the completion of the current Church building in 1891.
Tiffany decorated the apse beginning in 1895 with the installation of seven stained glass windows in the apse depicting, St. Michael’s Victory in Heaven. The windows were designed by Louis Comfort Tiffany in collaboration with Rev. John Punnett Peters and produced in Tiffany’s studio with the assistance of artists Clara W. Parrish, Edward P. Sperry, Louis J. Lederle and Joseph Lauber. Each measures five feet wide and twenty-two feet tall. Tiffany used as many as four layers of brilliant jewel tones glass to achieve the effects of sky, clouds and drapery. The hands and faces of the celestial figures as well as further details were also painted onto the surface of the glass.
Tiffany Glass and Decorating Company decorated the dome of the apse and installed the Vermont white marble high altar, reredos, credence niche, altar rail, pulpit and other apse decorations. By 1920, the Tiffany Studios decorations in the Chapel of the Angels were completed, including two more stained glass windows and the large mosaic, Gloria in Excelsis, behind the altar.
The dramatic four-armed mica panel cross lighting fixture hanging high above the apse as well as most of the fixtures in the Chapel of the Angels were also produced by Tiffany Glass and Decorating Company.
All of these works represent one of the largest installations of Tiffany glass and decorations to remain in its original setting.