Simms was an Internal Investigations agent from District.
Simms helped secure the building during the lockdown imposed by George Mason. Jack Bauer attempted to get past him, but Simms informed him of the lockdown and would not let him get work from his car. Jack then handed him his car keys, before slugging him and running out. Simms then reported Bauer's escape to Mason on the main floor shortly afterward. ("3:00am-4:00am")