"The process for replacement hasn't begun yet," George said on Tuesday.
George answered a handful of questions from the audience gathered at Saint Xavier University in Mt. Greenwood after a lecture he gave on the Second Vatican Council.
The Cardinal said the process to appoint a new leader to the archdiocese would take upward of nine months. He encouraged whomever is named to the post to speak with those around him and trust their advice.
"It's very important to listen to people and have them tell you the truth," George said.
His guidance came as the archdiocese announced that George's plans to travel to Rome for the canonization of two former popes had been canceled.
"That event will go on whether I'm there or not," he told the crowd at Saint Xavier, 3700 W. 103rd St.
The cardinal appeared frail as he approached the podium at the Southwest Side university. George said his doctors advised against the trip to Rome, citing his weakened immune system.
The archdiocese also confirmed on Tuesday that George has resumed chemotherapy after the discovery of cancer in his kidney.
George was previously treated for cancer in 2012 and 2006. He submitted his resignation in January 2012, though the move was largely seen as a formality required of all bishops at age 75.
The first Chicago native to be named archbishop of the region of 2.2 million Catholics, George was ordained less than a year before Vatican II. He said Mass in Latin for eight months before the rules changed.
He reflected on the purpose, goal and impact of Vatican II in his speech. He said lingering effects — both good and bad — can be traced back to the decisions made by Pope John XXIII and religious leaders that gathered in January 1959.
"The goal was to restore the unity of the human race," George said.
Prior to his presentation, Graziano Marcheschi introduced the cardinal. The executive director of university mission and ministry at Saint Xavier offered a glowing intro that listed George's many accomplishments.
Seemingly embarrassed by the gushing welcome, George used the introduction to open his speech with a bit of levity.
"One of the advantages to being seriously ill is you get to hear your obituary read in front of you," he said.