The nephew of assassinated president John F Kennedy initially launched a campaign for the White House, before later withdrawing to support Donald Trump.
The famous Kennedy family looks set to get an unusual route back to the heart of US government in 2025, courtesy of Donald Trump. The new president-elect is reportedly poised to offer a top job in his administration to his controversial former election rival Robert Kennedy Jr, also known as RFK.
Kennedy, the nephew of assassinated president John F Kennedy and son of murdered presidential candidate Robert 'Bobby' Kennedy had initially launched an independent campaign for the White House which threatened to derail both the Democratic and Republican campaigns.
He later withdrew and backed Trump, a situation which saw him urging his supporters not to vote for him after authorities in some states refused to remove his name from ballots.
As well as his famous name, his often eccentric views have frequently seen him in the spotlight during the race for the Oval Office.
Here, Yahoo News takes a look at some of the controversial things he has said.
Shortly before polling day, Kennedy took to X, formerly Twitter, to reveal his hope to remove fluoride from US drinking water.
"On January 20, the Trump White House will advise all U.S. water systems to remove fluoride from public water," he posted.
"Fluoride is an industrial waste associated with arthritis, bone fractures, bone cancer, IQ loss, neurodevelopmental disorders, and thyroid disease."
It was not the first time the former lawyer has spoken out on the issue, promising before he quit the presidential race he would "order the CDC [Centre for Disease Control and Prevention] to take every step necessary to remove neurotoxic fluoride from American drinking water".
However, both the CDC and the American Dental Association have noted low-levels of fluoride in the water supply is a safe way to prevent tooth decay, especially among children.
In the UK, health chiefs are hoping to expand the number of areas with fluoridated water to improve dental health, with risks dismissed as "exaggerated and unevidenced".
RFK was condemned by several members of his own family over comments he made about the COVID-19 pandemic.
Speaking in New York last year, he claimed the virus had been developed in China as a bioweapon.
"There is an argument that it is ethnically targeted. COVID-19 attacks certain races disproportionately," he reportedly told the event. "The people who are most immune are Ashkenazi Jews and Chinese."
He also claimed the disease was "targeted to attack Caucasians and Black people".
Claims COVID-19 emerged as a bioweapon have been made since the coronavirus pandemic started in 2020, with at least one UK poll finding almost 30% of Brits thought it had been spread by China on purpose.
Russia also alleged Ukraine had been the centre of a bioweapons programme ahead of its invasion.
However, such assertions have also been criticised as "scientifically invalid" and spread by proponents who are "suspected of spreading disinformation", according to US intelligence authorities.
RFK made several outlandish claims on The Joe Rogan Experience podcast last year, including that wi-fi and mobile phones can cause so-called 'leaky brain'.
"Wi-fi radiation does all kinds of bad things," he told the broadcaster, "including causing cancer."
He also claimed to be "representing hundreds of people" who had suffered brain tumours due to mobile phone use and that wi-fi could affect the blood brain barrier which is supposed to protect the organ.
While mobile phones can cause a range of health issues affecting sleep and mental health due to overuse, there is little evidence to suggest cancer is one of them.
As part of proceedings for his divorce in 2012, claimed he had suffered "cognitive problems" after a worm consumed part of his brain.
According to a recording of his deposition, he sought medical advice after fearing he was suffering form a brain tumour, only to be told a dark spot on scans was "caused by a worm that got into my brain and ate a portion of it and then died".
If chosen for a top job by Trump, RFK could also find himself subject to a federal investigation.
A 2012 interview with his daughter Kathleen recently resurfaced, in which she recounted the failed presidential candidate using a chainsaw to behead a dead whale which had washed up on a Massachusetts beach, before strapping it to the roof of the family minivan.
"Every time we accelerated on the highway, whale juice would pour into the windows of the car, and it was the rankest thing on the planet," she told Town and Country magazine.
Since then, RFK has confirmed he is being investigated by the National Marine Fisheries Institute over the incident.
"This is all about the weaponisation of our government against political opponents," he added, but did not deny the incident happened.