He invited Waller to help him create the new Monash Law School. On 1 June 1965, he was appointed Professor. Three years later, he was appointed Dean of Law, a position he held until 1970, after which he returned to focus on teaching and research. An apparently brilliant teacher, his students included future Justice of the High Court of Australia Kenneth Hayne, Chief Justice of Victoria Marilyn Warren, Federal Court and Supreme Court Justice Mark Weinberg and human rights lawyer Julian Burnside QC. Hayne later described Waller as an "electric" law lecturer, while Burnside has described him as "the best teacher I have ever seen". At Monash, he developed his expertise in the criminal law, and authored the first Australian casebook in that field. Through his teaching and research, he is credited with elevating the status of criminal law in Australia, a field which had often been looked down upon. He continues to author the leading casebook on Australian criminal law, now in its 10th edition. Waller developed particular interest in medical law and medical ethics. He wrote prolifically on in-vitro fertilisation, a practice which was coincidentally pioneered in the Medicine Faculty at Monash. At the Law Reform Commission, Waller chaired a groundbreaking committee which looked at the possible legal framework surrounding IVF for the first time. When the Victorian Government created the first IVF legislation, it largely adopted Waller's model. As his career progressed, he became recognised as one of Australia's leading scholars. In 1982, he became the first Law Reform Commissioner of Victoria and, two years later, became the inaugural Chair of the Victorian Law Reform Commission. His expertise in the field of medical law has led to appointments on a number of medical and judicial committees. He is Chairman of the Infertility Treatment Authority, the Appeals Committee of the Royal Australasian College of Surgeons, and the Ethics Committee of the Walter and Eliza Hall Institute of Medical Research. Waller formally retired from Monash Law School in 2000 as its most senior academic. However, he continued his teaching and research as Emeritus Professor of Law. Upon his retirement, the school established the Louis Waller Chair of Law in his honour. Waller was made an Officer of the Order of Australia (AO) in the 1989 Australia Day Honours for "service to the legal profession, particularly as a teacher, and to the community".In 2005 he received an honorary LLD (Doctor of Laws) degree from Monash University.