It was alleged that England international Hardaker had made inappropriate comments towards Saints forward Mark Flanagan.
However, the Match Review Panel has now confirmed that there was insufficient evidence for charges to be brought against the 22-year-old.
"The RFL can confirm that no further action will be taken following an investigation into an incident in the First Utility Super League fixture, Leeds Rhinos v St Helens played on Friday August 29," read an official statement.
"Details of the investigation were presented to the RFL Match Review Panel which concluded that there was insufficient evidence for charges to be brought."
Hardaker, who was handed a five-match ban for homophobic abuse towards a referee earlier this season, will be available for his side's Super League playoff against Catalans Dragons on Saturday.