A-level, AS-level and GSCE exams were cancelled in January due to the ongoing disruption caused by COVID-19.
Instead teachers used mock results, coursework and in-class assessments to determine students' grades this summer.
More than two in five sixth formers (44.8%) were awarded A or A* grades this year, which is up 6.3% on last year's 38.5%.
The number of students with A* grades has also risen dramatically - by 19.1% - which is the highest figure since A*s were introduced in 2010.
But the pass rate fell slightly by 0.2% from 99.7% to 99.5%, figures for England, Wales and Northern Ireland show. Scottish Higher results have been released separately.
Female students performed better than their male counterparts overall and managed to overtake them in A* maths results for the first time - with 29.1% of girls getting the top grade in the subject compared to 28.5% of boys.
Black pupils, those who get free school meals and are from very deprived backgrounds achieved lower results this year than before the pandemic in 2019.
This means the achievement gap between them and other pupils has widened by 1.4% during the COVID crisis.
UCAS figures show that numbers accepted onto their first-choice university course also increased by a record 8% to 395,770.
There was also a 5% increase in the number accepted on any course, with 435,430 going to study full-time.
Experts have warned that the new teacher assessments are causing grade inflation and "lower standards to become the norm".
According to an analysis by exam regulator Ofqual, some 6.9% of students in England were awarded three A*s this year - compared with 4.3% in 2020 and 1.6% in 2019.
Last year saw further accusations of grade inflation after the government was forced to U-turn on a controversial algorithm it introduced to make up for cancelled exams.
There was uproar from pupils and parents - with some threatening legal action - after the algorithm downgraded thousands of results.
But after a system overhaul, the majority of grades emerged higher than expected.
This year random and targeted sample checks were used to ensure teacher assessments were fair.
In total 1,101 schools and sixth form colleges in England were scrutinised by exam boards.
Ofqual said that 85% of the assessments looked at by them were satisfactory and the remainder will be subject to further scrutiny.
These "small number of centres" will be withholding results from pupils if the outcome of their reviews are not clear on results day.
Defending the assessment scheme, director-general of the Joint Council for Qualifications (JCQ) Dr Philip Wright said "teachers used their professional judgment in time for us to check and award grades".
"On behalf of JCQ and the exam boards, I would like to congratulate all students receiving their results today," he said.
"The impact of COVID has undoubtedly provided a difficult chapter in their education journey and their resilience is to be applauded. We wish them all the best as they take their next steps in life."