Ted Terry, 59, is accused of calling Amarjit Talafair a "f****** Paki" before headbutting him during a dispute over a cigarette outside a City of London pub on March 22 last year.
Giving evidence from the witness box at the Old Bailey, the self-employed decorator admitted he pushed his head against Mr Talafair's face but denied using racist language.
The jury heard that the Chelsea captain's father had received a 24-month conditional discharge for common assault in 2005 and a suspended prison sentence for an offence of supplying class A drugs in 2010.
Two months after being arrested for racially aggravated assault in March last year, Terry racially abused another man during a train station bust up, calling him a "f****** Irish prick", the court heard.
Cross-examining the defendant, prosecutor Alex Chalk asked: "Are you somebody who becomes aggressive in a heartbeat Mr Terry?
Terry replied: "I wouldn't say so, no."
"Are you someone whose aggression flashes up at the most trivial provocation?
The defendant replied "no".
"When you get angry do you lash out with the first thing that comes into your head, which in your case is racist abuse?"
Terry replied "no" again.
Later, Mr Chalk asked: "This was just another incident where you became angry and aggressive at the most trivial trigger, isn't it?
"And you are now simply coming here to wriggle out of your own racist temper, aren't you?"
Terry replied "no" to both.
Wearing a navy jumper over a sky blue shirt, Terry explained that having a star footballer son could be difficult.
Answering questions from his defence barrister, Alexia Power, he said: "People say 'look that's John Terry's dad over there' and come up to ask things, or they might come up to and have a go and say 'your son can't play football', but you just have to take it and walk away."
But he admitted that his son's fame had nothing to do with the fracas on March 22 or the later confrontation at Barking railway station on May 12.
Terry, of Lennox Close in Grays, Essex, denies one count of racially-aggravated common assault and one count of racially-aggravated fear or provocation of violence.
His work colleagues Stephen Niland, 36, of Quarles Park Road in Romford, Essex, and Tudor Musteata, 47, of Tarves Way in Greenwich, south east London, deny one count each of racially-aggravated fear or provocation of violence.