Gardner completed her PhD thesis, supervised by Professor Gordon Plotkin FRS at Edinburgh in 1992 and held five years of fellowships at Edinburgh. She moved to Cambridge in 1998 on an EPSRC Advanced Fellowship, hosted by Professor Robin Milner FRS. She obtained a lectureship at Imperial in 2001, and became professor in 2009. She held a Microsoft Research Cambridge/Royal Academy of Engineering Senior Fellowship at Imperial, 2005-2009.
Philippa directs the Research Institute on Verified Trustworthy Software Systems (VeTSS), funded by EPSRC and NCSC, 2017-2022. She is an organiser of the Isaac Newton Institute six-week summer programme on `Verified Software’, 2021. In 2020 she was elected a Fellow of the Royal Academy of Engineering.