ICE temporarily released José Gregorio González a Broadview facility in April.
According to his attorney, Peter Meinecke, González was granted supervised release for one year to care for his dying sibling and possibly donate a kidney to him.
González was detained by ICE earlier this year while accompanying his brother, José Alfredo Pacheco, to a dialysis appointment. Pacheco of Cicero had end-stage kidney failure and needed a transplant.
The Resurrection Project, the group representing González, said González successfully donated his kidney to Pacheco on Friday. The surgery was done at a Chicago-area hospital.
"Today we celebrate not just a successful surgery, but the triumph of love and community over fear and cruelty," Erendira Rendón, Vice President of Immigrant Justice at The Resurrection Project, said in a news release. "The fact that this feels like such an incredible victory speaks to how cruel our immigration system has become. Across the country, families are being torn apart as parents, caregivers, coaches, and partners are detained indiscriminately and jailed indefinitely in overcrowded facilities that put their mental and physical health at risk."
The Resurrection Project says González does not have a criminal background.
González could still be deported in a year.
ICE said in a statement in April, "Jose Gregorio Gonzalez, 43, is a citizen of Venezuela who has been ordered removed to his home country by an immigration judge... Gonzalez was arrested and placed in ICE custody March 3 without incident. After providing proper documentation ICE granted Gonzalez a temporary stay on humanitarian grounds."
ABC News contributed to this report.