Firearm trigger mechanisms with rotatable linkage members and associated systems and methods are disclosed herein. A firearm trigger assembly configured in accordance with embodiments of the present technology can include, for example, a trigger, first and second linkage members, and a sear. The first linkage member, second linkage member, and sear are arranged in an over-center configuration that securely locks the sear in a first position. Pulling on the trigger causes the trigger to rotate about a fixed pivot point and push on one of the two linkage members, forcing the linkage members and the sear out of the over-center configuration. The force from a striking mechanism forces the sear and the linkage members into a collapsed configuration, releasing the striking mechanism and firing the firearm. This two toggle configuration of the trigger assembly provides crisp and reliable release of the firearm.