In accordance with an embodiment, described herein is a system and method for autonomous firewall rule management, for use with cloud computing environments or other types of network environments. A firewall rule management automation framework provides rule management for firewalls deployed across availability domains. The system is adapted to automatically determine firewalls that can receive network traffic from a given source subnet or destination subnet; configure the firewalls with required firewall rules; monitor the firewall rules through collection of metrics snapshots and rule hit counts; and purge underused or potentially obsolete firewall rules, for example those having zero hits over a particular period of time or number of snapshots. The system provide generic support for different types of firewall devices, and autonomous management of firewall rules within large heterogeneous computer networks that may include several types of firewalls.