Speaking as doctors and students vote on the proposed junior contract, Dr Johann Malawana sought to reassure voters of the progress achieved through industrial action.
Speaking to the British Medical Association's conference in Belfast, Dr Malawana, who led negotiations as the government sought to avert an all-out strike, called for doctors to keep their "unity" as they decide whether to accept the contract proposals.
Some surveys have suggested that voters may reject the contract.
Dr Malawana said: "We were strong enough to make the government listen, to withdraw one red line after another, and to win for our members a number of significant improvements on those original plans – pay for all work done, a robust means to safeguard working hours, and financial recognition of weekends."
He added: "I know our members hold different views, but what I think is beyond argument is that we are only in a position to have anything to offer them because we stood up, together, for what we believe in.
"I think we have delivered a good deal despite unbelievable odds.
"Our unity must be maintained, because there is so much else for which we must fight together."
He went on: "I think the government picked a fight because they thought they could win. They thought the medical profession would just roll over. We didn’t, we shouldn’t, and I’m confident to say that in the future, we won’t."
* The BMA highlighted a letter received from a health minister yesterday promising to work with it to improve conditions for less-than-fulltime trainees.
The letter from minister Ben Gummer to Dr Malawana said that an organisation called the Social Partnership Forum would be used to investigate the problems.
Mr Gummer writes: "I am keen that we should all work together to understand the size of the problem and the barriers to supporting these valued staff.
"I believe that a specific element of the work should be around identifying any barriers to female doctors progressing at the same rate as male counterparts and making recommendations for addressing these."
Jill Watts, chief executive of BMI Healthcare, compared complacency about the NHS to the collapse of the British car industry last century.
Speaking to a private healthcare summit, she said the private sector could offer "support" to the NHS.
This included additional capacity, investment and even "new economic solutions."
But she went on, according to the Health Service Journal: “The NHS is clearly failing.
"The level of delusion that surrounds the NHS is similar to that of the British car industry that rather complacently thought it was the envy of the world.”
The proposal was adopted yesterday by the British Medical Association, which voted to campaign against the limits.
The pay caps were introduced in a bid to contain the rising NHS bill for agency staff.
But delegates at the BMA's annual conference in Belfast attacked the caps for reducing doctors' earnings below the rate of a driving instructor or fitness trainer.
It means the BMA will urge locums to refuse to work at hospitals that use the pay caps.
GP trainee Dr Thomas Micklewright told delegates that the rising cost of locums was because of problems in the NHS, such as staff shortages.
He said: “This is a disgrace. Locumming is an active career choice for many including working parents and foreign doctors. Pay has always been flexible to reflect need and urgency.”
There was backing from Dr Russell Walshaw, from Yorkshire, who warned of a crisis in medical staffing.
He said: "Locums work in all sectors of healthcare across the country and without them the providers would collapse. The supply is tight and good locums are worth a premium."
Workers now "treat" themselves to cakes almost daily as they celebrate birthdays or workplace achievements, according to Professor Nigel Hunt, dean of the faculty of dentistry.
Speaking last night in London, he warned that tooth decay in adults is a major problem.
According to the most recent figures, nearly 65,000 adults were treated in hospital for tooth decay in the year from 2014 to 2015.
He called for a culture change in offices to enable workers to resist treats of this kind.
Treats can often include boxes of chocolates "lying around the office all day," he said.
Professor Hunt said: “Managers want to reward staff for their efforts, colleagues want to celebrate special occasions, and workers want to bring back a gift from their holidays.
"But for many people the workplace is now the primary site of their sugar intake and is contributing to the current obesity epidemic and poor oral health.”
He added: “I’m not saying we need to ban such treats. But we do need a change in culture. When people are going out to the shops and buying cake and sweets they should at least consider buying smaller quantities and making them available only with lunch meals.
“Ideally office workers should consider other alternatives altogether like fruit platters, nuts, or cheese. Responsible employers should take a lead and avoid such snacks in meetings.”