Hennigan was in breach of an Asbo imposed in 2005 when a swastika was discovered daubed on the front door of his council house.
Prosecutor Lynne Shirley told the court that Tanisha Ford, a black Caribbean woman and her two children, aged eight and six and also black Caribbean, were in Market Square, Harlow.
She had recently moved to the town and was looking for a shop.
"She noticed the defendant waving at her," she said. "She approached him and he asked her if she was looking for a toilet. She said no, looking for Slimming World.
"He gave her directions. It seemed a normal conversation and she walked off but as she did Hennigan said 'I don't agree with inter-racial relationships. I like natural'.
"She was shocked and surprised and asked what he meant. He said 'I prefer white children'. She was shocked further. She said her children were natural and he said 'I'm just saying'," said the prosecutor.
"The incident made her feel very upset, hurt, out of place and distressed. It's not the first time she's been racially abused and it brought back unpleasant memories," said Miss Shirley. "She was alarmed her children had to listen to the comments."
Ms Ford decided to call police. Hennigan was identified and while he was in custody officers found comments he made "very unpleasant," the court heard.
Mitigating, Harry Warner urged the judge to spare Hennigan from immediate custody. He said: "It's not worked in the past and is unlikely to work in the future."
He could benefit from working with probation, he added. "He is a rather unfortunate man. He lives alone, is single and has been diagnosed and medicated for depression."
But Judge Lynch told Hennigan: "Your offence is thoroughly unpleasant and repeated breaches of this order using the most unpleasant of language and causing distress.
"It's said custody would be distressing for you but it seems you never learn. This is the ninth time you have breached this order, the same offensive, racist comments and you don't deserve another chance."
It was at this point that Hennigan began talking directly to the judge. He said he hadn't intentionally abused anyone "whatever you think".
Judge Lynch disagreed. She told him: "No one cares what you think." Hennigan responded: "I know they don't, that's why I've not had any help for years."
Judge Lynch said she was not going to argue with him and was sending him straight to prison. It was then that Hennigan began swearing at her.
He had been hauled before an Old Bailey judge in October 2012 for making Nazi salutes at a pub in Bishopsgate in the City of London.
Hennigan claimed he had only been raising his arm to collect his change after paying for a drink, but was convicted of breaching an Asbo after a trial.
Hennigan, from Harlow, Essex, has dozens of previous convictions for offences including drug and firearm possession and common assault.
He faced a court for breaching his Asbo in 2010, when he launched racist abuse at a newsagent before attacking him with a display of sweets.
