The election took place during a closed-door session of the House of Bishops at St Paul's Cathedral, Namirembe, where all 34 eligible bishops cast their votes in a secret ballot to choose a successor to Archbishop Henry Luke Orombi, who had announced his early retirement.
Under the Church of Uganda constitution, a candidate needed a two-thirds majority to be declared the winner. Ntagali, then serving as the first Bishop of Masindi-Kitara Diocese, secured the required support and emerged as the choice to lead the province.
His election was officially announced later that day at the Archbishop's Palace in Namirembe by the Rt Rev Nicodemus Okille, then Dean of the Church of the Province of Uganda.
Ntagali's elevation marked a significant moment for the Anglican Church in Uganda. Having spent eight years building and leading the relatively new Masindi-Kitara Diocese, he arrived at the provincial office with a reputation for steady leadership and strong administrative skills.
He was formally enthroned on December 16, 2012, at Namirembe Cathedral in a ceremony attended by church leaders from across Africa and beyond, as well as senior government officials.
His tenure was characterised by institutional growth and major administrative projects.
Among his most notable achievements was overseeing the completion of Church House in central Kampala, a long-delayed commercial development that became a key source of income for the church. He also presided over the creation of several new dioceses, expanding the church's administrative reach and bringing leadership structures closer to local congregations.
On the international stage, Ntagali became a prominent voice within the Global Anglican Future Conference movement, aligning the Church of Uganda with conservative Anglican provinces and defending traditional interpretations of scripture during debates that divided the worldwide Anglican Communion.
After serving as Archbishop for more than seven years, Ntagali retired on March 1, 2020, upon reaching the mandatory retirement age of 65.
He handed over leadership to Archbishop Stephen Kaziimba Mugalu, bringing to a close a period that saw significant structural and financial developments within the Church of Uganda.
His retirement was later overshadowed by personal controversy, including a suspension from priestly duties in 2021 and a public confession and apology at Namirembe Cathedral.