The current iteration of this 1843 coral-block structure dates from 1929. Originally classical in appearance, the church was given a Gothic Revival portico and tower in 1910, and plans were developed to remodel the building to conform to this style. This effort proved impractical and was supplanted by Spanish Mission with the installation of the red tile roof in 1926, and the Doric-columned portico in 1929. Reinforced-concrete buttresses and interior tie rods were added in 1941 to help support the weight of the new roof. The tower is the third to rise over the church, replacing an octagonal version during the 1890s. Its clock, the oldest public timepiece in Hawaii, was made in France in the 1820s and came to Our Lady of Peace by way of a mission in Valparaiso, Chile. The clock has been in continuous use since the mid-1840s. The church also presented Hawaii with its first pipe organ, which was shipped from France and installed in 1846.
The interior of the cathedral has been converted from a linear space to a circular seating arrangement to accommodate a congregation-oriented style of worship; however, the painted, redwood, barrel-vaulted ceiling and the gallery with its distinctive second-story pendant-drop arcade, the result of an 1871 remodeling, remain. The stained glass windows are the work of Mayer Studio in Munich, Germany, and date from 1929. One window includes a rendering of the cathedral as it appeared at the end of the nineteenth century.