Guzman is the second member of the budget team to announce a departure in recent days, and it comes just ahead of the crucial budget season. She is following the city's chief financial officer, Steven Mahr, whose last day was last Friday, out the door.
In the normal course of events, people coming and going from City Hall, perhaps, is not a big deal. But Guzman's decision to leave public service after 10 years at City Hall and before that, in senior financial roles at Cook County, means Johnson is losing another experienced money manager as the fall budget season approaches and a mayoral election looms in six months.
The mayor's office said Guzman is leaving to spend more time with her family.
"It has been an honor to serve under Mayor Johnson's leadership," Guzman is quoted in a statement from the mayor's office, adding, "and to support an administration that is committed to standing up for working residents and advancing a vision for a safer, more affordable Chicago."
She could be seen attending a budget committee hearing last month.
Guzman's move comes on the heels of a troublesome midyear budget update from the mayor's finance team, as the city faces a projected budget shortfall of nearly $100 million.
Chicago this month will host a gathering of investors as the city's bonds sit on the verge of junk status. Guzman's deputy, Jonathan Ernst, will step in as acting budget director.
The mayor will be expected to explain what's going on with his budget team on Tuesday.