Frankie Boyle has denied "punctuating" material with racist references or making "gratuitous" use of black people.
The comedian told the High Court that characters he played might express racist views but he did not.
He was giving evidence on the third day of a trial in London after complaining that the Daily Mirror libelled him by describing him as "racist comedian Frankie Boyle" in an article.
Boyle said he has actively campaigned against racism and parodies racists - and claims the newspaper "misunderstood" the context of his use of language in jokes.
Daily Mirror publisher Mirror Group Newspapers (MGN) is defending its article, published on July 19 2011. MGN lawyers have described Boyle as a "racist comedian" who gratuitously exploits negative stereotypes of black people for "cheap laughs".
On Wednesday, Boyle answered questions from barrister Ronald Thwaites QC, for MGN.
Mr Thwaites pointed to a joke about US President Barack Obama and said Boyle was making "gratuitous use of a well-known black man".
He added: "You are punctuating your programme with racist references that some people will find clever and others will find normal and acceptable."
Boyle denied the allegation and said he was playing characters who were "dressed up".
"These are phrases that a racist will use," he told jurors. "There is no way they are an endorsement of racist terminology. It is the absolute opposite of that." He added: "If I dressed up as Godzilla, people would not accuse me of wanting to crush Tokyo myself."