Javid quit dramatically quit as chancellor earlier this month rather than accept the ultimatum.
Speaking in the Commons on Wednesday, Javid said the demand would have prevented him from “speaking truth to power”.
“It has always been the case that advisers advise, minsters decide and minsters decide on their advisers,” he said in a speech from the backbenches.
With Johnson listening from the frontbenches, Javid added: “I believe that the arrangements proposed would significantly inhibit that and it would not have been in the national interest.
“So while I was grateful for the continued trust of the prime minister in wanting to reappoint me, I am afraid that these were conditions that I could not accept in good conscience.”
In a possible swipe at Dominic Cummings, Johnson’s chief adviser, Javid said he did not want to comment on all the “comings and goings, if you will” in government.
But he said he hoped Rishi Sunak, who replaced him as chancellor in the reshuffle, would be allowed to do the job “without fear or favour”.
Sunak agreed to accept No.10′s demand that he share his special advisers with the prime minister’s office.
Javid also warned Johnson to “keep spending under control” and “keep taxes low”.
“At a time when we need to do much to level up across generations, it would not be right to pass the bill for our day-to-day consumption to our children and grandchildren,” he said.
“It’s fair to say that not everyone in the centre of government feels the pressure to balance the books.”
Johnson thanked Javid for his “immense service” to government and said he had “friends and admirers” in all parties.
This article originally appeared on HuffPost.