It officially began operation on August 5, 2003, and became Canada's newest self-administered First Nation police service.

Nationally, standards for First Nations Constable recruitment and attendance at formal police colleges, varies from province to province, however since inception all Treaty Three Officers meet all applicable Ontario provincial training standards and attend the same courses as Ontario police officers.

Deputy Chief Larry Indian replaced Jones after three years, evacuating the unsafe and underfunded Couchiching OPP First Nations Program Detachment.

Assisting them were two Staff Sergeants, Jim Harty, Kenora detachment commander, and Richard Darling, head of administration.

Treaty Three has its own Crime Unit also based in Kenora led by OPP Detective Sergeant Rob Bears for several years until Doug McKenzie was eventually seconded in 2011.

After McKenzie returned to the OPP the crime unit was greatly reduced and supervised by Detective Sergeant Terry McCaffrey.

T3PS also uses the same personal equipment, radio and computer systems and training system (such as the annual "block training" in CPR/First Aid, recent case law, investigative techniques and Use of Force" ) as the OPP, since the majority of the equipment and operations used by the First nations program is still used by the current service, allowing ease of use, and greater cooperation between neighbouring forces until T3PS can provide its own in-service training units and new police facilities.

Introduced in 2003 in time for the graduation of the first 14 officers hired and subsequent ceremony in Kenora was the dress uniform.

Due to the vast patrol area, (55,000 square miles) T3PS was divided into two major "sub-divisions" with smaller satellite detachments left over from the OPP administered program.

Territories in the Rainy River district operated out of the Emo OPP detachment east of Manitou Rapids First Nations while Couchiching sub-division was relocated between fall of 2007 and spring 2011 from Couchiching First Nation near Fort Frances, Ontario while the new building was approved and constructed.

Starting in March 2013, Treaty Three Police was forced into a position of laying off officers due to a chronic shortage of funding.

In an effort to keep Treaty Three Police Service in existence, Police Chief Conrad Delaronde and the Chiefs of the communities it serves, had ignored the collective bargaining agreement, introduced a number of cost-cutting measures such as wage cuts, and eliminated paid maternity leave, which effectively reversed a recent arbitration decision to bring the officers to OPP parity.

The Treaty Three Police Officers Union opposed these measures and requested the Board of Directors abide by the current contract, which expires in March 2014.

Within hours of the announcement, a grassroots Facebook movement arose to generate support for the officers, questioning the speed, wisdom and legality of the decision to "bust the union".

The layoff notice was then rescinded by Chief Davidson and the new board in preparation for a new effort to work with the officers and PSAC to negotiate a new contract, seek better funding while addressing community concerns within the current budget.