But he didn't know his final call would come early in his career.
A team playing bag pipes started the procession, followed by Sgt. Johnson's casket draped in the U.S. flag.
His wife carrying their young son followed the casket into the Maverik Center arena where thousands of law enforcement stood at attention.
"Go forth my brother to fill the calling you have answered," his brother Darin Johnson told those in attendance. "There is not a moment that will go by that I will forget you."
Governor Gary Herbert also spoke at the funeral. He quoted from scripture saying "greater love hath no man than this, that a man lay down his life for his friends. Sgt. Johnson has demonstrated his love for his family in our community."
His brother says Sgt. Johnson was a tireless officer. And on September 1, when he was gunned down allegedly by a man in a car, Darin Johnson says his brother was only doing what he did every day.
"This truly exemplifies your dedication and courage," says Darin Johnson. "You could have just drove by wrote that car off but you stopped to assist as the humble servant that you are. In a moment you were taken from us and my heart bleeds. But I know you were needed somewhere else."
Those in attendance learned Sgt. Johnson's smile was magnetic and could light up a room when he entered.
"He is my only brother and I love him," says his sister-in-law Amanda Fralick. "Make sure you smile today because that's what he would want."
His sister recalled Sgt. Johnson wanting to become an officer at a young age and practiced police maneuvers on her. But it was his dedication to his work that impressed her the most.
"I promise I will never forget you," says Desirae Johnson. "I will watch for signs of you everywhere I go."
It has been a rough week for the Draper police department. The police force and city workers were seated together near the casket. Those who worked alongside him recalled a man who loved wearing the badge.
"It didn't matter what time it was, he worked and worked," says Sgt. Pat Evans who also was Johnson's best man at his wedding. "I was jealous of his work ethic, his honesty, his integrity, he's the best."
His police chief was in awe of Sgt. Johnson's keen sense of law enforcement, attention to detail and understanding the police handbook and offering recommendations.
Chief Bryan Roberts says he will be missed but his department will carry on.
"It's going to be tough dealing through this but we will do it that what we do in law enforcement. to protect and to serve," says Chief Roberts. "We never falter. We will always serve the public and we will continue to do that we will do it in Derek's honor."