Azeem Rafiq has apologised and said he is "deeply ashamed" for using anti-Semitic language in Facebook messages from 2011.
Former spinner Rafiq has spoken of his experiences of racism at Yorkshire and appeared at a Digital, Culture, Media and Sport select committee this week.
The 30-year-old said he had "absolutely no excuses" for the messages.
"I am incredibly angry at myself and apologise to the Jewish community," he said in a statement.
Rafiq also later apologised on Thursday for an Instagram meme containing a saying relating to African people.
He said posting this four years ago "was a matter of stupidity but the harm is the same as overt racism so that is no excuse".
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The Facebook messages, first reported by the Times, were sent between Rafiq and another cricketer.
Rafiq said he had deleted the messages to not cause further offence.
"I have absolutely no excuses. I am ashamed of this exchange," he said.
"I was 19 at the time and hope and believe I am a different person today."
Warwickshire have said they will have a "detailed conversation" with former player Ateeq Javid, who exchanged the messages with Rafiq.
Claudia Mendoza, co-chief executive of the Jewish Leadership Council, said Rafiq had "undoubtedly" learned a lot since 2011.
"There's no doubt that this is massively awkward for Azeem Rafiq," Mendoza wrote on Twitter.
"But he's taken full ownership, apologised, and undoubtedly - through his own experiences - learnt a lot about racism since then."
Marie van der Zyl, president of the Board of Deputies of British Jews, said: "Azeem Rafiq has suffered terribly at the hands of racists in cricket so he will well understand the hurt this exchange will cause to Jews who have supported him.
"His apology certainly seems heartfelt and we have no reason to believe he is not completely sincere."
Rafiq's Instagram meme was used to make a derogatory point about some family members.
"I copied this post from Facebook during a family dispute," Rafiq said.
"Clearly, I should not have copied this post and I apologise for the hurt this has caused. I don't know what on earth I was thinking.
"I have been clear over the past 16 months that I have made many mistakes and two of them have quite rightly been brought to the public's attention today."
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Rafiq has spoken powerfully about his experiences of racist abuse when he played for Yorkshire in 2008-14 and 2016-18.
He first spoke out in September 2020, claiming "institutional racism" at Yorkshire left him close to taking his own life.
Yorkshire conducted an investigation that concluded Rafiq was the "victim of racial harassment and bullying" and apologised, but were heavily criticised for the way they handled Rafiq's complaints.
The club also said no-one would face disciplinary action following the report.
Speaking to the DCMS select committee on Tuesday, Rafiq described English cricket as "institutionally racist", and that racist language was "constantly" used during his time at Yorkshire.
He also graphically described being pinned down as a teenager and having wine poured down his throat while playing for his local club.
Barnsley Woolley Miners Cricket Club, who Rafiq played for as a teenager, said they take the claim very seriously and would welcome "any independent investigative body to provide the transparency that a serious allegation of this nature deserves".
"We did initiate a search of our welfare records and contacted our former safeguarding officer and there is no record of any incident being reported at that or any other time," a statement read.
"If Azeem wants to provide those details, we will of course initiate an investigation.
"For the record, the club would not have allowed such behaviour to take place unchallenged if it had been aware."
Former Yorkshire academy players Irfan Amjad and Tabassum Bhatti have also alleged they received racist abuse while at the club.
Essex are facing racism allegations and encouraging those who have experienced discrimination to come forward.
Earlier on Thursday, former Yorkshire and current Somerset bowler Jack Brooks "unreservedly apologised" for two tweets, sent in 2012, which contained racist language.
Brooks also apologised for calling India batter Cheteshwar Pujara 'Steve' when they were both at Yorkshire.