"Following a thorough operational test, fielding of the modular handgun is expected to begin in 2017, " the Army said in a statement announcing the decision Thursday.
The M9's three decades of service since 1985 has occasionally made it the subject of derision among members of the armed forces.
"The joke that we had in the military was that sometimes the most effective use of an M9 is to simply throw it at your adversary, " Sen. Joni Ernst, a former officer in the Iowa Army National Guard, said last week during the confirmation hearings for Ret. Marine Gen. James Mattis to be secretary of defense.
The multi-year effort to replace the Beretta has been slammed by members of Congress.
"The Army's effort to buy a new handgun has already taken 10 years and produced nothing but a more than 350-page requirements document micromanaging extremely small unimportant details, " Senate Armed Services committee chairman John McCain wrote in a 2015 report on the program's problems.
"A decade for a pistol?" Sen. Thom Tillis of North Carolina asked at the same Mattis confirmation hearing. "They're relatively simple devices ... This is a great testament to what's wrong with defense acquisition."
But Army Acquisition Executive Steffanie Easter promised that as the program moved "forward into operational testing, the due diligence taken by all of the stakeholders will ensure a program that remains on-budget and on-schedule."
Sig Sauer's P320 pistol is believed to be the model on which the new handgun will be based. The Army is seeking certain modifications that are not being made public.