Leeds City Council said around 7,300 year 11 pupils in the city received their results with some schools reporting marked improvements.
Council chiefs said provisional results show an increase in the proportion of young people in Leeds achieving a strong pass of grade 5 and above in English and maths.
Overall, one in five entries nationwide took the top grade equivalent of at least an A, which is now marked as a 7 under the new system, with two-thirds awarded a 4 or above, which equates to a grade C.
There had been fears that the new system, marked by major reforms and a move away from coursework and modular exams, would impact on students taking tests for the first time.
But with slight rises nationwide across the overall pass rates, and for those taking top grades, students have been given reason to celebrate.
The vast majority of entries in England were for the new-style GCSEs this year, with 20 subjects, including the sciences, foreign languages, history and geography moving over to the system.
They join English and maths, which were awarded numerical grades for the first time last summer.
Lisa Williams, deputy headteacher of Allerton High School in Alwoodley, Leeds, said “I think they have been tougher. There have been more exams, every subject has had more papers.
“The children found the new qualifications unnerving, but they have risen to the challenge and done extremely well across all subjects.
“It doesn’t matter whether they call the grades letters or numbers as long as the process is fair and students have a chance to show their potential, which they have had.
“The overriding feeling is that students got what they worked for, and that’s fair.”
More than 10 per cent of Allerton High School GCSE students achieved a clean sweep of top grades and two thirds of students achieved a grade 5 or higher in both English and maths.
Identical twin sisters Marwa and Safa Ahmed achieved top grades across the board despite English being their third language.
The Allerton High school students from Alwoodley, who speak Urdu as their first language and Punjabi as their second, achieved a total of 15 grade 7 to 9 GCSEs between them.
Deputy head Lisa Williams, said: “The girls act as role models and mentors for those younger students at school who struggle to communicate because English isn’t their first language.
“Not only have they helped others to do well in these exams, their own personal achievements are exceptional.
“They will be coming back to the sixth form in school where they will do more work with younger students as well as study A level sciences with a view to careers in medicine.”
Allerton High student Jude Spellacy, of Chapel Allerton, achieved seven GCSEs at grade 9 and two at grade 7 despite crashing his bicycle and breaking his right elbow while cycling to school for his first exam.
He sat the first biology paper before going to accident and emergency, but he could not write and had to read out his exam answers to a teacher who wrote them down.
Jude, who achieved a grade nine in biology, said: “It was difficult in the exam, but it was fine in the end as I was given extra time.” He added: “I’m really pleased with the results.”
Among high achieving students at Guiseley School are Finn Cartwright, who notched up nine grade 9 GCSEs along with an A* and an A* distinction in further maths.
Guiseley School students James Allen and Isabelle Richmond both achieved seven grade 9s, with Lucy Morrish, Curtis Lack, and Eleanor Sawyer managing an admirable three Grade 9s.
High achieving students at Woodkirk Academy include Maia Cole, who got six GCSEs at grade 9 and four at grade 8.
A total of 83 per cent of Woodkirk Academy year 11 pupils achieved a pass in English and 85 per cent passed maths.
Robbie Strathdee was one of four Horsforth School students who achieved a minimum of eight GCSEs at grade 9.
Other students who excelled were Mia Sudbury, James Wordsworth and Shirley Xu.
A total of 83 per cent of the school’s students achieved a standard pass in English and maths.
Headteacher Dr Paul Bell, said: “We are so proud of the hard work and dedication of our students and pleased they have been rewarded with wonderful results.”
Niamh Cassidy was the top performing GCSE student at Cardinal Heenan Catholic High School in Leeds.
Niamh achieved seven GCSEs at grade 9 and three at grade 8.
A total of 68 per cent of the school’s pupils gained passes at grades 9 to 4 in five subjects including English and Maths.
Headteacher Dominic Kelly said: “Congratulations to all involved and particularly to retiring Headteacher Peter Whelan.”
Grace Tran was the highest achieving GCSE student from John Smeaton Academy in East Leeds.
Grace achieved five GCSEs at grade 9, four at grade 8 and one at grade 7.
A total of 51 per cent of students achieved five or more GCSEs at grade 9 to 4, including English and maths.
Head of school Claire Bailey, said: “These achievements lay the foundations for the next stages of their school careers.”
GCSEs in England have undergone sweeping changes including a new grading system as part of education reforms that began under the coalition government.
Traditional A* to G grades have been replaced with a 9 to 1 system, with 9 being the highest mark.
In general, a grade 7 to 9 is roughly equivalent to A to A* under the old system, while a grade 4 and above is roughly equivalent to a C and above.
Fewer students will receive a grade 9 than would have received an A*.
English and maths GCSEs were the first to move to the new numerical grade system last summer with another 20 subjects added this summer. The new courses feature much less
coursework and pupils now take all of their exams in most GCSE subjects at the end of the two-year course.
Coun Jonathan Pryor, Leeds City Council’s executive board member for learning, skills and employment, said: “I would like to congratulate everyone who has taken their GCSEs this year for the hard work and effort that has gone into achieving these results.
“Exams are a difficult and stressful time but with the help and support of their families and schools, students have done themselves and the city proud.
“Support, advice and guidance is available to those young people still considering their future options after receiving their results.”
Students will be able to find out about options at sixth forms and colleges across the city at a Next Steps event at Leeds Kirkgate Market from 11am to 2pm on Thursday August 30.
Go to www.leeds.gov.uk/leedspathways/results