From Priest to Bishop
Maximus served as a priest in Jerusalem, where his endurance in persecution and his character brought him widespread popular respect. When Bishop Macarius of Jerusalem sought to appoint him to the vacant see of Lydda (Diospolis), the people of Jerusalem refused to let him leave, so Macarius appointed another man to Lydda instead.
Maximus became bishop of Jerusalem upon the death of Macarius. OrthodoxWiki dates his tenure as bishop from 334 to 350.
The Arian Controversy
In 335 Maximus attended the First Synod of Tyre, an Arian-dominated council, and signed its condemnation of Athanasius of Alexandria — an act he later repudiated. He soon recognized his error and became, in the words of his biographers, a dedicated enemy of Arianism.
Around 346 he convened a synod of sixteen Palestinian bishops that welcomed Athanasius back from exile and restored to him communion and rank. This synod also served to advance the ecclesiastical standing of Jerusalem in relation to Caesarea.
The Church of the Holy Sepulchre
A major act of his episcopate was the dedication of the newly constructed basilica of the Church of the Holy Sepulchre in Jerusalem.
Deposition and Repose
According to the historian Sozomen, the Arians Acacius of Caesarea and Patrophilus of Scythopolis deposed Maximus around 350. Theodoret reports that Maximus had intended to appoint Heraclius as his successor, but that Acacius and Cyril of Jerusalem subsequently deposed Heraclius instead. Rufinus calls the succession irregular without giving further detail.
Maximus's precise date of repose remains uncertain, likely occurring shortly after 350.
Commemoration
The saint is commemorated on May 5. Sources also record an Eastern Orthodox feast on May 9 (locally) and August 26 (universally), while the Roman Catholic Church observes his feast on May 5.