Having retired from Clinical Practice in July 2025, he was appointed as an Honorary Medical Officer, Diabetes Centre Bankstown-Lidcombe Hospital, Sydney. He was Department Head, Diabetes & Endocrinology and Director, Diabetes Centre Bankstown-Lidcombe Hospital, Sydney Feb 1987-Dec 2023 (Co-Head of Dept 2022-Dec 2023). Main area of clinical research interest is Information Technology applications in Medicine, especially Data sets and Quality Audit initiatives involving Diabetes Data collection, analysis and reporting. He developed [with Professor Stephen Colagiuri] the Australian National Diabetes Information Audit and Benchmarking initiative, [ANDIAB], that collated diabetes data from Specialist Diabetes Services in Australia and benchmarked results for participants to review their process and outcomes data with peers. ANDIAB ran as a Pilot in 1998, thence in 1999 - 2011. He Chaired the National Diabetes Data Working Group [NDDWG] until 2012, the Advisory Committee to the National Centre for Monitoring Diabetes (Incorporating the National Diabetes Register) at the AIHW. He served on the Australian Diabetes Society Council from 2000-2006 and was ADS President 2004-2006. He is a Conjoint Professor, School of Medicine Western Sydney University (from 1st June 2015) and was a Conjoint Associate Professor, Faculty of Medicine UNSW (2004 to June 2025). In August 2014 he was awarded Honorary Life Membership of the Society, he received an ADS Award for 'Outstanding Contribution to the Australian Diabetes Society including ANDIAB, and an Annual 'ADS Jeff Flack Diabetes Data Award' was created. Professor Flack received an AM in the Australia Day 2016 Honours List.