Docherty played a starring role as the Tigers drew 1-1, before netting the first penalty as Hull won a dramatic shootout.
The League 1 side were seconds away from winning in regulation time, having led since a Mallik Wilks strike in the fifth minute.
Leeds grabbed a lifeline when Ezgjan Alioski equalised in the fourth minute of stoppage time.
But weren’t to be denied and Docherty was on target with their opening kick as they went on to win the shootout 9-8 and book a third round trip to West Ham United.
Docherty joined Hull City during the summer after leaving boyhood idols Rangers, having failed to establish himself as a regular under Steven Gerrard despite successful loan spells at Shrewsbury and Hibernian.
INTERVIEW: Greg Docherty not ruling out Rangers return at some stage.