"This isn't about an individual. It's about an organization moving forward," Edmonson told The Associated Press. "I think it's time for me to move on."
He delivered his retirement paperwork to Gov. John Bel Edwards on Wednesday morning. Edmonson's last day at work will be March 24.
Concerns had been raised about thousands of dollars his agency spent on a trip to a law enforcement conference in California and about a nonprofit trooper organization's donations to political candidates despite bans on political contributions from troopers.
Although one of Louisiana's U.S. senators had urged Edmonson to leave the job as controversy swirled, the chief said Edwards did not ask him to step down.
"I was not asked and did not resign. I retired, and I retired with the blessings and support of the governor. We've had several conversations over the last few days and not one time did the governor ask me to resign," Edmonson said.
"My head's held high, and I walk out of here at my own request," he said.
Edwards said he agreed with Edmonson that "this is the best approach for the department." He credited Edmonson with "innovative thinking and concern for our state" and thanked him for his long service.
"Throughout many natural and man-made disasters, Col. Edmonson has been a steady hand and strong leader for the people of Louisiana," the governor said in a statement.
Edmonson has been with the state police for 36 years, starting as a patrolman and later overseeing the public affairs office, commanding security at the state Capitol and managing the training academy. His face was familiar to LSU football fans because of his longtime role as security escort for the head coach.
He was appointed superintendent by Republican then-Gov. Bobby Jindal in 2008. Edwards, a Democrat, kept him in the position, an unusual decision.
Amiable and confident, Edmonson was the face of state police responses to hurricanes, massive flooding, a movie theater shooting in Lafayette, protests after the police shooting of Alton Sterling and the ambush-style killings of three law enforcement officers in Baton Rouge. He didn't shy away from the attention in such sensitive situations.
The exiting superintendent hopes his tenure will be remembered for bolstering partnerships between state police and other law enforcement agencies, boosting trooper salaries, using new technology in crime-fighting and working to combat human trafficking.
"He's obviously someone that the sheriffs, myself included, respected. He was a team player, a collaborator," said Jefferson Parish Sheriff Newell Normand, a Republican.
But Edmonson has been under fire from blogs and a social media site allegedly run by anonymous troopers accusing him of misconduct and mishandling agency finances.The criticism grew louder since February when The Advocate newspaper reported state police spent thousands on overtime and expenses for troopers who drove to an October conference in San Diego with a state SUV, diverting to a Las Vegas casino resort and the Grand Canyon on the way.
In response, Edwards said his administration has an auditor digging into state police travel. Rep. Blake Miguez, R-Erath, asked Louisiana's legislative auditor to review the agency's trip expenses during Edmonson's tenure as superintendent, saying he was concerned about "alleged misuse of state taxpayer funding." U.S. Sen. John Kennedy called on Edmonson to resign, saying he's wasted money while Louisiana struggles with budget gaps.
Meanwhile, the Louisiana State Troopers Association — an organization of current and retired troopers — and its executive director were fined $5,000 by the state ethics board this year for funneling $17,500 in illegal political contributions to Edwards, lawmakers and others.
The organization is an independent entity, but says it represents 97 percent of commissioned officers — who are overseen by Edmonson.
Despite the controversies, Edmonson received praise Wednesday from law enforcement leaders.
East Baton Rouge Parish District Attorney Hillar Moore, a Democrat who has known Edmonson for three decades, called him a leader in developing "cutting-edge" protocols for police shooting investigations and said he helped turned the state police crime lab into one of the nation's best.
"I really hate to see him go," Moore said.
The recent dust-ups aren't the first political firestorms during Edmonson's tenure.
In 2014, lawmakers passed a retirement hike that would have benefited Edmonson and one other trooper. The change, which would have cost $359,000, passed without public scrutiny on the last day of the legislative session. After harsh criticism, Edmonson and the trooper said they wouldn't accept the increased benefit, and a judge declared the pension hike unconstitutional, saying it wasn't passed properly.AP reporters Michael Kunzelman and Kevin McGill contributed to this report.