The former Columba College pupils studied law at the University of Otago - Emma (25) finished in 2009 and Alice (21) last October.
Overseas travel and a job with the New Zealand Defence Force delayed Emma's completion of the Legal Professional Studies Course, so when Alice finished her degree they decided to do the course and be admitted together.
''It's a big honour to do it together in front of the family,'' Emma said.
Alice said being a lawyer at the age of 21 felt ''surreal''.
She left secondary school after year 12, having gained discretionary entry to university, and earlier this year overcame meningitis.
It was a ''gutsy'' effort, their mother Wendy O'Connell said.
Emma will continue working as a member of the Defence Force's civilian staff in Wellington and Alice will soon travel overseas, although the sisters plan to practise as lawyers in the future.
Mr Kahn (47) is the great-grandson of Alfred Hanlon, who was admitted to the bar at Dunedin 125 years ago and became one of the city's most renowned criminal advocates, best remembered for representing murderess Minnie Dean, ''the Winton baby-farmer''.
Dean was the first and only woman to be hanged in New Zealand following her conviction for murder in 1895.
Hanlon was born in Dunedin in 1866 and attended Otago Boys' High School before starting work as a law clerk at the age of 15.
His legal career spanned more than 50 years, during which time he appeared in courts nationwide.
Mr Kahn said it was fitting his admission to the bar took place in Dunedin, given his great-grandfather's history.
Formerly a telecommunications consultant, Mr Kahn began his bachelor of law degree at the University of Canterbury, in Christchurch, but moved to Dunedin last year after his home was destroyed by the earthquakes.
He praised Otago University for allowing him to complete his degree and planned to work in commercial litigation.rosie.manins@odt.co.nz
