Campbell has faced calls to resign from many in the community as well as Illinois Governor JB Pritzker.
In a statement, Campbell said in part, "The tragic death of Sonya Massey has been a heartbreaking event for our community. ... Since the incident, I have been proactive and transparent, working tirelessly to present all of the facts to the public. I have committed to making changes to our standards and collaborating with other units of government on ways to prevent incidents like this in the future. The one person truly responsible for this act is in jail, and I believe justice will be served through the legal process."
"Despite these efforts," the statement continues, "some in our community want me to pay the price for that person's actions, even threatening that I pay that price with my life, my family's lives, or the lives of my Deputies. ... But it has become clear that the current political climate has made it nearly impossible for me to continue effectively in my role. Some individuals would rather see our community divided and in turmoil, than allow me to continue serving as Sheriff. The health of me and my family, the Sheriff's Office, and our community has to be my priority."
Former Sangamon County Deputy Sean Grayson shot and killed Massey inside her Springfield home in July after Massey called 911 to report a possible intruder.
Sean Grayson, the 30-year-old Sangamon County sheriff's deputy who has since been fired from the agency, was indicted by a grand jury on three counts of first-degree murder and one count each of aggravated battery with a firearm and official misconduct in connection with the July 6 shooting at Massey's home near Springfield.
Grayson has held six different jobs in law enforcement since 2020. He also had two DUIs on his record before entering law enforcement.
RELATED: Sonya Massey, mom called 911 multiple times in days before her death
Wednesday, Governor Pritzker called on Campbell to resign.
"I called for the sheriff's resignation because the sheriff has failed," Pritzker said. "He has failed to explain how he ended up hiring this deputy sheriff who has been fired from other departments."
Pritzker also blasted Campbell for not meeting with Massey's family.
"I'm not saying that is a fire-able offense to not meet with them, but that seems outrageous to me; at a minimum listen to them, hear them and then hopefully take action," the governor said.
READ ALSO | Audio recordings reveal deputy involved in Sonya Massey killing was scolded by previous supervisor
In an interview with ABC News last week, Campbell said Grayson's background did not strike him as a red flag.
"The fact that multiple agencies is a plus the way we look at it, he was not fired from any of them," Campbell said at the time.
Campbell said he was unaware of concerns from a previous employer. Records show a Logan County Sheriff's Office supervisor reprimanded Grayson for inaccuracies in police reports. Campbell said he never saw the records during his hiring process.
"We didn't file a FOIA request, we rely on it voluntarily to be given to us," he said.
Campbell said his retirement will be effective no later than August 31.
Full statement from Sangamon County Sheriff Jack Campbell
I was first elected Sheriff in 2018. I embraced that role, to lead SCSO, but I always saw myself as a cop, not a politician. And for over thirty years, my career has been dedicated to improving and protecting our community. As Sheriff, I have committed my life to advancing our capabilities and effectiveness, implementing new policies and practices to ensure we serve the community with the highest standards of integrity and professionalism. All this was done with the idea of creating a safer Sangamon County.
The tragic death of Sonya Massey has been a heartbreaking event for our community. My deepest condolences go out to her family and friends. Since the incident, I have been proactive and transparent, working tirelessly to present all of the facts to the public. I have committed to making changes to our standards and collaborating with other units of government on ways to prevent incidents like this in the future. The one person truly responsible for this act is in jail, and I believe justice will be served through the legal process.
Despite these efforts, some in our community want me to pay the price for that person's actions, even threatening that I pay that price with my life, my family's lives, or the lives of my Deputies. We will only persevere together as a community if we turn down the temperature and resolve to do better. We must honor the life of Sonya Massey by ensuring that no one else falls victim to such tragic and senseless action. That has been my sincere mission since that fateful day. But it has become clear that the current political climate has made it nearly impossible for me to continue effectively in my role. Some individuals would rather see our community divided and in turmoil, than allow me to continue serving as Sheriff. The health of me and my family, the Sheriff's Office, and our community has to be my priority.
As elected leaders, we must always put the overall good of the community above ourselves; and I will not risk the community that I swore to protect. For this reason, I am announcing my retirement as Sheriff of Sangamon County, effective no later than August 31st.
While it is painful to say goodbye, I do so knowing I have fulfilled my duties and served to the best of my ability. I want to express my deepest gratitude to the citizens who have supported me throughout the years. I am forever grateful for the opportunity I had, for the people I met and for this Office that I love.
Jack