The Bank of England's chief currency dealer Martin Mallett was sacked for "at least 20 breaches of protocol" - some of which were unearthed during a parliamentary grilling into how much the bank had known about this.
"We discovered a series of misjudgements that Mr Mallett had made unrelated to the Grabiner inquiry," Carney told the Treasury Select Committee.
"There were at least 20 examples of this."
This included leaking a confidential document, using inappropriate language on multiple occasions, sending emails with inappropriate attachments, and giving his own opinion over the bank's.
His sacking was announced in November and was due to the central bank's internal policies, rather than the forex scandal. In unfortunate timing, though, it did come on the same day six banks were fined £2.6bn by regulators over the forex scandal.
The Grabiner inquiry found Mallet failed to escalate concerns over the behaviour of forex traders from 2008, which was thought could involve collusive behaviour and disadvantage market participants..
"Mr Mallett did not act in bad faith," the report said.
"He was not involved in any unlawful or improper behaviour, nor was he aware of specific instances of such behaviour. In particular, he was not aware of the improper behaviour with which the FCA is concerned that goes far beyond his own concerns about potential misconduct."