Between 1298 and 1305 John Sandale served as Warden of the Mint.
In 1307 John Sandale was appointed Chancellor of the Exchequer. He was dismissed the following year.
In 1310 John Sandale was appointed Lord High Treasurer which office he held until 1311. Between 1312 and 1314 he was acting Lord Treasurer.
On 26th September 1314 John Sandale was appointed Lord Chancellor.
Life of Edward II of Carnarvan by a Monk of Bridlington. Likewise, in the same year, the see of Ely fell vacant, and John Hotham was appointed to it. The see of Winchester likewise fell vacant, and John Sandale was admitted to it at the King's insistence.
Item eodem anno episcopatus Eliensis vacavit, cui præfectus! Johannes de Hothome, et Wyntoniensis similiter, cui Johannes de Sandale ad regis instantiam est admissus.
On 26th July 1316 John Sandale was elected Bishop of Winchester.
On 31st October 1316 John Sandale was consecrated Bishop of Winchester.
In November 1318 John Sandale was appointed Lord High Treasurer which office he held until his death.
On 2nd November 1319 Bishop John Sandale died.