In this Malay name, there is no surname or family name. The name Abbas is a patronymic, and the person should be referred to by their given name, Ahmad Nizam. The word "bin" or "binti"/"binte" means 'son of' or 'daughter of', respectively.
Ahmad began his career as a criminal defence lawyer, before specialising in family law.[5] As a defense lawyer, he was involved in the case of Ghazali Abdul Manaf, a prisoner who was beaten to death by prison officers.[6] He also represented Tan Eng Hwa, a man who was jailed for six months for loitering and "appearing to be waiting for a chance to commit a crime".[7] In 2013, Ahmad represented a pair of Chinese hotel chefs who had received bribes from a seafood company.[8] In 2023, he represented former auxiliary policeman Mohamad Fazli Selamat, who was convicted of the manslaughter of his stepdaughter and sentenced to 15 years and 11 months' imprisonment and 12 strokes of the cane.[9]
He worked at Straits Law Practice before joining Emerald Law as a senior partner, subsequently founding his own firm, Crescent Law Chambers.[10][11][12] In 2023, he was appointed deputy chairman of Simba Law Alliance, a coalition of regional law firms in Southeast Asia.[13]
Ahmad has been a member of numerous boards and committees, including Mediacorp, the Mendaki Club, the National Youth Forum, the Censorship Review Committee, and the Law Society's Muslim law practice committee.[14][15][16][17] He wrote a number of op-eds on the Today newspaper on his work at the National Youth Forum.[18][19] In 2006, he was projected to run for political office in Tampines, but did not end up doing so.[20] In 2021, he became a founding member of Defense Fund SG, an initiative that provides pro-bono legal support to victims of sexual harassment.[21][22] For his work in public service, he was awarded the Pingat Bakti Masyarakat in 2007.[23]
Ahmad is also active in legal publication. He wrote the first Muslim family law textbook in Singapore.[24][25]