When Roger Bede Vaughan, a former monk of Downside Abbey, arrived in Sydney as Polding's coadjutor bishop in 1873, he was elected by the fellows as rector.

[clarification needed][4] The carved Gothic-style reliquary box in the chapel contains the skull of St. Bede the Lesser, a Benedictine monk who died before AD 1000.

The relic had been preserved in a reliquary in the church of St. Benignus at Genoa, served by the Benedictine monks of Monte Cassino until the early 19th century.

The relic was transported to Sydney by the missionary priest Martial Mary and presented to Archbishop Vaughan while he was residing in the college.

Wardell originally designed St. John's College as a three-story sandstone Gothic Revival building on an H-shaped plan.

When Blacket was appointed to supervise the construction of St John's, several changes were made to Wardell's specifications: Australian hardwood was substituted for pitch pine, bar trusses were used in the chapel, a fountain was dropped from the plans, common rather than fire bricks were used, Portland stone was replaced by Colonel stone, and ornamental pillars were incorporated into the design of the library.

Designed by one of England's (and Australia's) foremost ecclesiastical architects of the mid-19th century, it is unique in Sydney collegiate architecture in its combination of scale, quality and construction.

It is a notable example of the period when Pugin's insistence on archaeological accuracy was giving way to the more eclectic influences of the High Victorian generation.

Built entirely in sandstone, the college is 14th century English Gothic in style, and substantially Renaissance Baroque in plan, in the manner of Wardell's earlier monasteries and convents.

The arrangement of the ground floor entry vestibule, and the formal, axially linked Imperial staircase are equally classical in inspiration.

The formal parts of the building are very grand, particularly if compared to the almost domestic scale of Blacket's contemporary St Paul's College.

Continuing south along the visitor's line of entry on the main axis is a visually low, dark vestibule.

The chapel is covered by a high wooden roof Many of the sanctuary furnishings are believed to have been designed by Blackett in the 1860s, including the Blessed Sacrament shrine, which is made of Bondi Gold sandstone, the tabernacle, cedar choir stalls and pews.

The chapel contains five stained glass windows, three of which were commissioned in 1918 from John Hardman and Co., Birmingham, with the design based on the writings of St. Bonaventure, quoted by Cardinal Newman.

The sanctuary features an oak reredos and panelling designed by Herbert Wardell, as well as two life-sized carved statues of the Virgin Mary and St. John the Evangelist, which were made by Koffmefer of Munich.

Each truss is visually supported by short stone shafts with foliate capitals and corbels in the early 14th century manner, as is the tracery.

The formal entry stairs intended to be placed to the south have never been built, and the original eastern wall has been replaced by an open arcade.

The Great Hall has on display a collection of portraits of past visitors, rectors, fellows, and students, with the most significant portrait being Archbishop Polding / Gallery oil painting of Archbishop Polding DSB, 1866, by Eugene Montagu Scott (1835–1909), which was originally commissioned for St Mary's Cathedral.

The western windows contain the coat of arms of William Bernard Ullathorne, Cardinal Moran and Archbishop Kelly.

In 1918, Wardell's son, Herbert, working with his partner George Denning, designed what is known as the '38 wing (it was eventually begun in 1938), estimating the cost at £14,000.

The Polding Wing was built on the west end of the South Range in 1967 and opened by Sir Roden Cutler and blessed by Archbishop James Carroll on 26 November 1967.

Catholic Mass is celebrated in the chapel weekly on Sundays at 5.30 pm during the academic year, and on other important liturgical occasions.

All students of the college are encouraged to worship as a community, and the chapel is kept open at all times for prayer and personal reflection.

There are ample occasions during the academic year when either black tie or lounge suit for men and ballgown or evening gown for women are worn, depending on the event.

The Rawson sports are played throughout the university year, including cricket, rowing, rugby, swimming and diving, soccer, tennis, basketball, and athletics.

Major events each year include a college play, an informal, and two black tie formal, balls, and the intercollegiate debating competition.

Arts of Gold is a bi-annual event which showcases the artistic talents of St. John's students to raise money for a selected charity.

Capella Sublima have been recorded for broadcast by ABC Classic FM and numerous other Sydney radio stations.

Students are present from the United States, Canada, China and Hong Kong, Great Britain, Ireland, New Zealand, Zimbabwe, and South Africa.