The service took place at the Apostolic Church of God, at 6320 S. Dorchester Ave., in Woodlawn, from 2 p.m. to 8 p.m.
"It's not an easy day at all. It's been rough. It's been a rough week. And today's even tougher," said Lt. Larry Anoman, who was Ankum's mentor on Tower Ladder 34.
Even though Ankum had been with the department a little more than a year, Ankum seemed to leave a lasting impression.
"He lived for the job. He was happy every day being there. He was just a special type of guy. He'll never be replaced," Anoman said.
Ankum was on his second fire of the day last Wednesday, when the roof of an abandoned laundry gave way, also killing Chicago firefighter Edward Stringer.
"It's been a horrendous week for all of us," said Tom Ryan, President of the Chicago Firefighters Union Local 2. "We still have our jobs to do. It just makes it difficult when something like this weighs as heavily as it does."
Another firefighter who was treated and released from the hospital after the fire was re-admitted Wednesday after developing "complications," an official said.
When tragedy hits the fire department, the support is incredible to witness. There's bunting and processions beneath extended fire ladders, as well as the attendance of first responders from around the area.
"Even though you didn't meet the person, you're here for the family and their brothers on their company," said Evanston firefighter Kevin Roche.
Ankum, 34, is survived by a wife and three children, including a 1-year-old son. Relatives said they're crushed Ankum died so young.
"He's going to be dearly missed," said Eleazer Ayers, a distant cousin, who had tears falling down his face as he recalled how Ankum, as a youngster, used to play at his home on Halsted. "It's really hurting to see any young person lose their life, especially at work. I'm going to keep him in my prayers as he goes off to another life."
Visitation resumes at 10 a.m. Thursday, and his funeral follows at the same location at 11 a.m. Ankum's remains will be interred at Lincoln Cemetery in Alsip.