The base of the Chapel follows an ellipsoidal structure, following the initial circular foundation laid in the time of Ascanio Vitozzi. The curved walls are decorated with black Fabrosa marble that adds to the somber ambiance and features prominent arches and vertical pilasters. Guarini's pilasters have capitals of the Corinthian order that are artistically encircled with a crown of thorns and a passion flower in the center where three nails emerge like the stigmata of an actual flower. The floor is made of inlaid marble arranged in concentric circles.

Preceding the chapel's dome is the truncated drum that sits on top of the walls of the chapels. It consists of three large arches that create lunettes and pendentives in the spaces between. Each lunette and pendentive has a circular window through which light enters and flushes the chapel in sunlight. The arches are engraved with nails of the Passion, and on the lunettes are motifs of the Greek and Jerusalem crosses and stars.

The second level of the drum elongates the base of the dome, taking the total height of the structure to another level. The base is that of a ring walkway on which tall arched windows are supported. The light through the windows illuminates the drum and the dome above it. Between the arches are decorative niches. Above them are geometric motifs that are symbolic in nature.

The dome is possibly the most impressive part of the chapel. Composed of six levels of six overlapping arches each, the dome towers upwards and culminates in a suspended golden star at the top. When looked at from below, the dome resembles an almost transcendental geometric pattern of six hexagons aligned on top of each other, with divine light pouring through the windowed crevices.

In the center of the chapel is a platform with balustraded rails. An altar made of black marble and decorated with gilded wood is surmounted on it by Piedmontese architect and engineer Antonio Bertola. The Shroud of Turin was positioned in the center of the altar and inside a glass encasing. A golden grating, almost like a cage surrounds the casing. . The altar is placed such that it allows viewing of the relic from the sides. Much of the altar was destroyed in the fire and has seen undergone intense restorations.

In the 19th century, monuments dedicated to the members of the Savoy family were installed in the recesses of the chapel's arched walls. The figures include those of the first Duke of Savoy, Amadeus VIII, Emmanuel Philibert, Thomas of Savoy, and Charles Emmanuel II, under whom much of the chapel was completed.