Current District Attorney Steve Cooley has previously announced plans to retire from his post after three terms.
Trutanich, who made the official announcement on Thursday, said Los Angeles County Sheriff Lee Baca and other law enforcement professionals have strongly urged him to run.
"I love my job as city attorney, but I can't do my job to protect residents - nor can our local police and sheriffs - without a crime fighting partner in the DA's office," Trutanich said in a statement.
During his career, Trutanich has been involved in fighting gang crime. As an L.A. County Deputy District Attorney, he was involved in cases prosecuting gang members.
"I will never back off when it comes to violent gangs who threaten our schools and neighborhoods," he said, adding that mere arrests will not stop the city's gang problem.
Instead, as district attorney, he plans to expand anti-gang programs in local schools and support more mentoring and job training for area youth.
To further highlight his plans to reduce gang violence, Trutanich announced that Baca along with Tom Torlakson, teacher and California superintendent of public instruction, will serve as honorary co-chairs of his campaign.