As Secretariat for the Economy, Pell took on the task of cleaning up the Vatican's accounts. Each of the 136 departments operated separately, with their own inexact records and standards.
Last year, Pell hired auditing firm PricewaterhouseCoopers to help untangle the mess. By the time the audit was called off, he'd already found 1.4 billion euros "tucked away" and unrecorded, according to the Journal.
Yet, Pell has no plans to stop with his efforts, despite losing much of his mandate in June.
"My job is to keep pushing," Cardinal Pell said in a June interview. "The goal is that the Vatican will be recognized inside and outside the church around the world as somebody who handles their finances properly and appropriately."
Most of the Holy See's revenue comes from the Vatican Museums, real-estate holdings and investments. The Vatican Bank, which acts independently and finances the Catholic Church across the globe, provided 50 million euros in 2014.
According to financial statements released in 2014, the Vatican had a deficit of 26 million euros. Last year, Pell estimates a deficit stood at 35 million euros or more.
Pell did find a potential new source of revenue in commercial and residential spaces in Rome valued at 1 billion euros and managed by the Administration of the Patrimony of the Holy See, or APSA. According to the cardinal, the management wasn't up to par, and in July 2014 Pope Francis gave Pell control of the properties.
However, APSA's president, Cardinal Domenico Calcagno, recently became close to Pope Francis, often seen dining with him at the Pope's residence. Over the course of 18 months, Francis removed Pell's control over APSA's real estate. Some blame Pell's belief in the free-market, of which Pope Francis is a well-known critic.
Pell previously united over half-a-dozen colleges in his native Australia into one national Catholic university. As Sydney's archbishop, he managed to triple the archdiocese's budget.
Currently, Australian authorities are investigating Pell over allegations of sexual abuse of minors decades ago, as well as accusations of failing to report abuse by other clerics during that time. He has categorically denied the accusations about his own behavior.
"Claims he has sexually abused anyone, in any place, at any time in his life are totally untrue and completely wrong," the cardinal's office said in a statement, from The New York Times.