The dean of an Oxford college who was suspended last September after being accused of “immoral, scandalous or disgraceful conduct” has won a tribunal hearing and will be reinstated next week.

Martyn Percy, the dean of Christ Church college, will return to work after a tribunal chaired by a former high court judge dismissed the complaints against him following a hearing behind closed doors in June.

A statement posted on Christ Church’s website said: “Following a thorough investigation, the tribunal has decided that the charges are not upheld and that there is no cause to remove the dean as head of house. However, the tribunal made some criticism of the dean’s conduct and found that there was one breach of his fiduciary duty.

“We can therefore announce that Martyn Percy will resume his duties as dean of Christ Church on his return from holiday on 27 August. The complaint process has now concluded.”

Steven Croft, the bishop of Oxford, said in a statement: “I am delighted to learn that this matter is now resolved. I look forward to seeing Martyn return to the cathedral and his duties as dean of Christ Church.

“This news will be widely welcomed across the diocese of Oxford. These have been testing times for all involved, and my prayers are with Martyn and [his wife] Emma, the chapter and wider college in the coming months.”

Christ Church, founded by Henry VIII in 1546, is the alma mater of 13 British prime ministers, 10 chancellors of the exchequer and 17 archbishops. Among its former students are King Edward VII, Albert Einstein, Lewis Carroll and WH Auden. It is one of Oxford’s richest colleges, with funds of more than £500m.

The details of the complaints against Percy, who has been dean since 2014, were not made public, but the college told alumni in a letter in January that the row related to pay. Percy – who is both college head and dean of the cathedral – is believed to earn about £90,000 a year plus accommodation and generous perks, which is relatively low compared with other college heads.

Governance of the college is also believed to be an issue in the dispute. Some members of Christ Church’s governing body were thought to oppose Percy’s efforts to modernise the arcane management of the college and reform its pay structures.

Under the college’s statutes, there are limited circumstances in which the dean can be removed. These include persistent failure or neglect of duties; being convicted of an offence that renders the dean unfit for office; physical or mental incapacity; and behaviour of an “immoral, scandalous or disgraceful nature”.

Percy’s supporters were furious that the wording was allowed to circulate for several months before the college clarified it did not relate to personal or sexual impropriety. One supporter described Christ Church as a “medieval fiefdom”.

Another supporter, the author and priest Angela Tilby, who is a canon emeritus of Christ Church, said Percy had sought to speed up reform at the college. “He wanted Christ Church to be more inclusive, more open to the outside world, and, perhaps, more aware of its wealth and vested interests,” she wrote in Church Times last year.

The hearing, presided over by Sir Andrew Smith, was expected to cost the college at least £500,000. Percy was forced to spend thousands of pounds to hire lawyers for the tribunal.