A utility cart includes an auxiliary swivel caster wheel assembly, a locking mechanism, and a trigger mechanism for causing the locking mechanism to releasably lock the auxiliary swivel caster wheel assembly. The auxiliary swivel caster wheel assembly is unlocked to enable the auxiliary swivel caster wheel to rotate about a vertical axis for improved maneuverability in small areas, and is locked to hold the auxiliary swivel caster wheel in a predetermined position for improved steering as the cart is moved from one location to another. The trigger mechanism is disposed on a steering handle to enable dynamic actuation of the locking mechanism while the cart is in motion.