Brady, 31, of Cross Bedford Street, Sheffield, was jailed for four months.
Judge Jeremy Richardson QC told Brady his attacks on Mr Wootton had “everything to do with your craving for celebrity status and your irritation that the press were not in the least interested in your somewhat uninteresting life.”
At Sheffield Crown Court, the judge said Brady’s claims Mr Wootton was in some way responsible for Miss Flack’s death were “wholly irrational”.
He pointed out the former executive editor of The Sun was a friend of the Love Island presenter who died in 2020.
Earlier this week, Brady admitted harassment at a hearing.
Judge Richardson said he would be released in the “very near future”, given the time the defendant served on remand.
He imposed a 10-year restraining order banning Brady from contacting Mr Wootton, posting anything about him online, or going within 200 yards of his home or workplace.
Judge Richardson blasted the social media posts and messages about Mr Wootton as “utterly outrageous”.
He issued Brady a stark warning he could face more prison time for breaching the restraining order.
In a statement read to the court, Mr Wootton – who watched the proceedings by video link – said he “adored” the “late, great Caroline Flack”.
He added: “I only ever wrote stories about Caroline that she wanted to be published.”
The journalist added: “She knew I had her back.”
Mr Wootton said the late presenter called him after ending her relationship with The Apprentice star.
The broadcaster said Brady had his phone number following a trip to an O2 concert arranged by Miss Flack so he could meet the defendant because she knew Mr Wootton had reservations about their relationship.
Mr Wootton said in his statement: “The public should be aware that he (Brady) has no credibility to speak on behalf of Caroline.”
But he added: “I hope he gets the help he needs.”
The court was read a message sent to Mr Wootton by Miss Flack which said of Brady: “He is scary, Dan. Still scares me even when he’s in Australia.”
The court heard how Brady’s campaign began on the year’s anniversary of Miss Flack’s death and involved what the judge described as “deeply unpleasant nonsense” across a range of platforms.
Laura Marshall, prosecuting, said other journalists were included in the defendant’s messaging including one who said Brady had demanded she pay him £40,000 for a “tell all” story about his former fiancée.
Ms Marshall said one message Brady posted about Mr Wootton said: “Felt like getting rid of him once and for all.”
She said WhatsApp voice messages left for the presenter included comments like: “You are culpable for people’s deaths” and “you are an evil man who needs to be dealt with”.
The court heard how Brady was arrested and bailed in February 2021 but continued his campaign against the journalist.
When he was arrested again, in April 2021, Brady livestreamed the event on Instagram, saying: “You’re going to have to put a bullet in my head.”
The judge was told Brady accused Mr Wootton of being a sex offender and a murderer during a two-month long campaign and compared him to convicted disgraced film producer Harvey Weinstein.
Judge Richardson said it was “deeply offensive criminal conduct” and described it as “irrational” and “narcissistic”.
He said: “You wholly irrationally purported to blame (Mr Wootton) in some bizarre way for (Miss Flack’s) death. It must be made clear that nothing could be more removed from the truth.”
The judge said he was “entirely satisfied” that Brady’s “catalogue of abuse” had “very little to do with the death of Miss Flack”.
Judge Richardson said he would not “sully” his sentencing remarks by repeating some of the “kaleidoscope of invective laced with high octane expletives”.
The judge told Brady: “Put simply, you must stop doing what you do.”
He explained to him the consequences would be severe if he resumed his campaign.
He told him: “Please mark my words. If that should happen, the likely sentence, given the history, will be measured in years not months.
“You have been warned.”