He also brushed aside reports suggesting he's taken firmer control of the White House staff than his predecessor, Reince Priebus, and cut off freewheeling access to Trump and the Oval Office. But two viral images of have fuelled speculation around discontent. "All of you", Kelly said, to laughter.
'It's amusing, I read in the paper - you all know you write it - that I've been a failure at controlling the president, or a failure at controlling his tweeting and all that, ' Kelly said - as he faced the White House press corps and provided assurances that he was neither quitting nor getting fired.
And he defended Trump's Thursday morning tweet in which the president threatened to pull federal help from hurricane-ravaged Puerto Rico, noting, "the whole point is to start to work yourself out of a job".
Kelly elected to explain his after a week of reports on turmoil within the White House, fueled by comments from Republican Senate Foreign Relations Committee chairman Bob Corker comparing the White House to "adult day care" and casting Kelly as one of a trio of senior figures averting 'chaos'.
But on Thursday, Kelly tried to put an end to the chatter - at least for now - explaining that his job is simply "really, really hard work". Whenever he's asked what he thinks of Kelly, Trump says, "He was a General!" All of you. Not all of you, but many of you.
I don't mean any criticism to Mr. Trump's predecessors, but there is an very bad lot of things that were, in my view, kicked down the road that have come home to roost, pretty much right now, that have to be dealt with. "Maybe develop some better sources".
"Is this the iron hand that I brought to the staff?" the former Marine general said, with apparent sarcasm. "This is, in my view, the most important job I ever had".
Nielsen was Kelly's chief of staff while he was Homeland Security secretary.
"The American people should be concerned about a state that has developed a pretty good ICBM capability and is developing a pretty good nuclear re-entry vehicle". He has been frustrated in particular with Secretary of State Rex Tillerson, who was reported last week to have earlier called the president a 'moron.'.
Kelly also said of Trump: "I hear him most say about nuclear weapons that, "Wouldn't it be great if we could get rid of them all?' as opposed to 'We need 10 times more".
John Kelly speaks during a press conference.