His Eminence Elder Metropolitan Joachim of Nikomideia and Exarch of Vithynia was born in Constantinople. He graduated from the Theological School of Halki in 1966 and was ordained a Deacon receiving the name Joachim. He served in the Patriarchal Court as a Deacon "in Order," and subsequently as a Defterevon Deacon until his promotion to Auxiliary Bishop of Melitinis in 1973.|
On March 25, 1974 he was appointed Chancellor of the Ecumenical Patriarchate serving successfully in this capacity for eighteen years. In 1977, he was promoted to active Metropolitan of Melitinis, thus reactivating the Metropolis of Melitinis. During his long tenure in the Chancery he served as Patriarchal Locurn Tenens in the absence of the Ecumenical Patriarch, and contributed greatly in the renovation of the Patriarchal Edifice and the Library. In 1990, His Eminence accompanied His All Holiness Dimitrios on his historic visit to the United States.
On September 21, 1996 Metropolitan Joachim presided at the Enthronement Ceremonies for His Eminence Archbishop Spyridon of America at the Archdiocesan Cathedral of the Holy Trinity in New York City. In recognition of his many and valuable contributions, and upon the recommendation of Ecumenical Patriarch Bartholomew, the Holy and Sacred Synod of Constantinople elected him unanimously Metropolitan of the Senior See of Chalcedon on December 10, 1991.