Salamoni's lawyer, John McLindon, said he anticipated the department will fire both officers for a violation of policies as a result of the shooting, but that both officers are planning to appeal such firing.
The announcement comes just over a year and a half after Sterling's killing, which was recorded on video shot from at least two vantage points.
But his decision is not the last chapter of the case, as the police department plans to hold hearings on whether to discipline the officers, and says it intends to release four videos that have yet to be made public.
Earlier Tuesday, Louisiana's attorney general ruled out state criminal charges against Salamoni or Officer Howie Lake II.
"I believe it's a foregone conclusion", McLindon said. He says he hopes to complete the disciplinary process by Friday. Sterling was outside the Triple S Food Mart in Baton Rouge when the officers came to investigate a call of a man with a gun threatening someone. One had been previously involved in the shooting of another black man two years prior that had led to administrative leave. "They said it was justifiable, what happened to Alton was justifiable". McMillon is the mother of one of Sterling's children, Cameron.
Now, the officers involved in the controversial incident have managed to skate free of charges.
Civil rights activists have blamed the officers for escalating tensions during the arrest in a convenience store parking lot and turning it into a deadly encounter.
The shooting sparked widespread protests.
Attorneys for Sterling's relatives have said federal authorities told them that Salamoni pointed a gun at Sterling's head and threatened to kill him before the struggle began.
"The Louisiana Department of Justice can not proceed with a prosecution of either Officer Howie Lake or Officer Blane Salamoni", Landry told reporters after meeting with members of Sterling's family in private.
Officer Blane Salamoni shot and killed Sterling during the struggle.
The officers recovered a loaded revolver from Mr Sterling's pocket. Before the fatal shooting, one of the officers can be heard yelling, "He's got a gun!"
She said she could not understand the decision. "He was murdered like an animal", Sterling's aunt, Veda Washington-Abusaleh, told reporters in video posted on social media by local media after being informed by Landry's office that no charges would be brought.
Attorneys L. Chris Stewart and Brandon DeCuir, who represent Alton Sterling's five children, said Landry met Tuesday morning with Sterling's relatives and their lawyers in Baton Rouge.