St Leonard's College was founded in 1512 by Alexander Stewart, Archbishop of St Andrews, and John Hepburn, Prior of St Andrews. The Archbishop, as Chancellor of the University, had wanted to reorganise the Pedagogy and erect it into a proper college. However, he was diverted from his intention by the Prior who was able to provide an endowment, and the new college came to be a 'college of poor clerks' associated with the Priory of St Andrews, primarily intended for the education, in arts and theology, of novices of the Augustinian Order. The charter of 1512 reveals that the college was a new incarnation of 'the Hospital and the Church of St Leonard joined thereto', which antedated the Cathedral, being already in existence in 1144. In 1747 the College was united with St Salvator's College to form the United College of St Salvator and St Leonard.
The original hospital or hospice of St Leonard seems to have been used by pilgrims to the shrine of St Andrew. Its location was on the western edge of the ecclesiastical settlement to the south of the eastmost part of South Street. The chapel is first mentioned in 1413 as 'the parish church of St Leonard within the city of St Andrews', served by a chaplain attached first to the hospital and latterly to the College under the title of 'curate'. St Leonard's Church was one of the buildings used for the earliest meetings of the University of St Andrews from 1411. There are references to the hospital or almshouse of St Leonard between 1421 and 1511 but the nature of the institution at that time is obscure.
The 1512 foundation was located on the site of the hospital adjacent to the church of St Leonard at the north-west corner of the Priory precinct. The buildings of the college were formed around a court and included church, library, common hall, schools, chambers and lodgings for staff. The college buildings were renewed and extended from the early seventeenth century. The north side of the court was rebuilt as schools and students lodgings after the hall and other buildings had been destroyed by fire in 1702. Despite the fact that its buildings were in better condition, the St Salvator's site was chosen to be the seat of the combined foundation after 1747. St Leonard's buildings were used by members of the United College until 1757 while repairs were being made to the St Salvator's site. The chapel was used until 1761, when St Salvator's Church was brought back into use as St Leonard's parish church. The buildings of St Leonards, other than the chapel, were sold off, the detached site in the Priory in 1754, the other college buildings in 1772. The latter were divided into St Leonard's East and St Leonard's West. After 1861 these buildings were leased back to the University for use as a collegiate residence for students as 'St Leonard's Hall'. This successful enterprise encouraged the Principal to proceed with the erection of a new Hall (1868) which survived only until 1874 when it was sold to Bishop Wordsworth who named it 'Bishopshall'. In 1881 the old residential buildings were bought by St Andrews School for Girls (founded in 1877) which, after its arrival on the site, assumed the traditional name and became St Leonard's School. The school eventually acquired all the adjacent property other than St Leonard's Church. The church had been reduced to bare walls in 1761 but was re-roofed and re-glazed by the University in 1910. It was completely renovated in 1948-52.
The foundation was on the authority of Pope and King and was confirmed by James IV in February 1513. No papal confirmation was ever given but Cardinal David Beaton confirmed it in his capacity of Apostolic Legate. Students studied for four years in Arts and were taught by the same Regent for all subjects. Teaching was structured through the faculties but the teachers and students were affiliated to one of the colleges. The 'New Foundation' of the colleges of the university of 1579 restructured the teaching in the university and St Leonard's College became primarily a 'college of philosophy' or arts. The principal of St Leonard's was to lecture on the philosophy of Plato. In 1620 Sir John Scott of Scotstarvit instituted a professorship of humanity, to teach the Latin necessary to enable the students to participate in the work of the philosophical courses. Eventually this professor found a place on the foundation but the other professors continued to teach all the subjects of the four year curriculum to one class in turn despite the requirement of the New Foundation that they should specialise. In 1702 Greek and in 1727 Natural Philosophy became fixed professorships but it was not until 1744 that complete specialisation was achieved.
In its first form St Leonard's College consisted of a Principal Master who was to be a Canon of the Priory and a graduate in Theology, four chaplains of whom two were to act as regents or teaching masters and twenty scholars in arts. This was slightly altered in the revised college statutes of 1544 to a Principal, two Priests (one of whom was to act as curate of the parish), four Regents and a variable number of scholars. In 1545 a fresh charter was issued to the college by Cardinal Beaton, reserving ultimate control of the College to the Priory, although in practice the management of its finances as well as the regulation of its community life was conducted by the Principal and his senior colleagues. They also had a role in the wider university as officials and examiners. At the Reformation of 1559-60 the Priory remained in being under its titular head the Commendator and its rights over St Leonard's College were maintained by the Sub-Prior John Winram. In February 1513 the College was granted all the property of the old hospital to which large additions were made in 1522. Most of the property was in the form of real estate and this provided a secure and long-term endowment. By the early eighteenth century most students completed their four year course in Arts but final examinations and disputations had fallen out of use. Very few took the degree of Master of Arts. The decline in student numbers, disrepair of the buildings and small salaries for the professors led to the amalgamation of the two philosophy colleges into the United College on 24 June 1747.
The great humanist George Buchanan (1506-82) was Principal from 1566-70. The College of St Leonard was reconstituted in 1974 as a notional entity to care for the interests of all postgraduate workers in the University. Although the present College has no buildings, it retains its spiritual focus around the restored Chapel of the medieval College and Deans Court, opposite the original college site, converted into a residence for research students in 1952. The Provost of St Leonard's College today remains the vice-principal of the University with oversight of the post-graduate community.