Hoff is a third-generation firefighter who once rescued two children from a burning building. His resignation comes on the 50th anniversary of his father's death while fighting a fire.
Hoff was named fire commissioner by then-mayor Richard Daley in 2010. His successor was named Thursday.
Hoff is a legend in Chicago firehouses, where firefighters worry that his resignation might signal dramatic changes to come in the historic department. It was fitting that his retirement news conference was held in a fire station, where he has always felt most comfortable.
"You can be a chief, you can wear a lot of bugles, but what makes you a good chief or makes you a good commissioner are the people that work under you," Hoff said.
Commissioner Hoff arrived early at Engine 42 to spend as much time as possible with firefighters with whom he has lived and worked for the past 35 years.
"He's an inspiration," said Chicago firefighter Justin Reynolds. "He is, and I hate to use the term, a fireman's fireman."
A third generation fireman, whose father was killed on the job 50 years ago, Hoff built his own legend during three decades of service. He twice won the department's highest award for bravery and was severely burned fighting a fire in 1984.
Chicago Fire Department Lieutenant Marty Chapman remembered Hoff, the battalion chief in 2004, manning the hose during the super-hot LaSalle Bank fire.
"Here he is, a big chief, and he's still hanging on to that pipe. The definition there is fearless," Chapman said.
Mayor Rahm Emanuel, who said he learned of Hoff's plan to resign four weeks ago, designated Deputy Commissioner Jose Santiago to lead the department without publicly opening the application process.
"You may want open, and I understand that from a media perspective, I want thorough as mayor. We ran a thorough process and have the best person to do this," said Emanuel.
Budget-minded Emanuel has not ruled out eliminating some stations and reducing the number of firefighters on trucks to get savings that Hoff has told the mayor compromise safety.
"The safety of the firefighters, the brothers and sisters of Local 2 of Chicago Fire Department was his No. 1 priority," said Tom Ryan, IAF Local 2.
"We'll make a determination based on safety," said Fire Commissioner-Designate Jose Santiago.
Hoff, who plans to teach after he leaves the department, said he will be available to both sides when the union and city begin negotiations on a new firefighter contract.
"It will be something that Jose and I will deal with, and something that we will deal with as we work through these issues together as we deal with Local 2," said Emanuel.
Commissioner Hoff said his decision to retire was personal and had nothing to do with his differences with the mayor on possible cuts to fire stations and staffing.
Santiago is a 33-year department veteran. He is a former Marine, known for his bravery, and well respected within the Chicago Fire Department.