Johnson, 32, joined the force in 2004 and was promoted to sergeant in 2012, the same year he won an award for excellence in community policing.
He was shot to death Sunday morning as he pulled up to a silver Volvo parked at an odd angle on 13200 S. Fort Street and a man opened fire on him.
But it wasn't his violent end the more than 1,000 gathered to remember Sunday night on the back steps of Draper City Hall, but rather his diligence and dedication.
Draper City Councilman Troy Walker said Johnson "was a stickler for doing it right."
"He was a great young man," Walker said. "I'm personally going to miss him."
Draper Mayor Darrell Smith thanked the attendees for their support, calling it an "amazing sight" as he looked out over the soft glow of hundreds of candles and the street and parking lot lined with American flags.
He said he thought of Johnson as a son and that the young man "brought a lot of good to the community."
Other members of the council praised Johnson for his service.
A tearful Bill Rappleye said Johnson was always there to serve.
"I will miss Derek," he said.
Vigil attendee Jessica Sant, a criminal justice student at the University of Utah, first met Johnson while volunteering at the Juan Diego High School peer court. She had planned to go to City Hall on Tuesday to set up an internship with the peer court where she would once again work with Johnson.
Through tears, she said he had "a smile at every turn" and was always good to work with.
Residents were asked to turn on their porch lights until Johnson is laid to rest. While funeral plans are still being finalized, the gesture will serve as a show of support for his fellow officers who will see the lights on as they patrol the city, leaders said.