Professor Humphris will succeed Julian Crampton, who is retiring after 10 years in charge at the university.
The academic, who originally qualified as a nurse, leaves Imperial after overseeing its teaching and learning strategy for the past three years, firstly as pro-rector for education and then vice-provost (education).
She was previously pro vice-chancellor (education and student experience) at the University of Southampton from 2008, where she was also professor of health care development.
Professor Humphris, who gained a PhD in 1999 on how policy is implemented into clinical practice, said she was “delighted” to be Brighton’s next vice-chancellor.
“This is a successful institution with a very exciting future and I look forward to working with students, the students’ union and with staff as we step up to the next level.”
Brighton has 21,000 students at five campuses stretching across the city and nearby Eastbourne and Hastings.
The university's chancellor, Lord Mogg, said Professor Humphris had a “wealth of experience and skills as an innovator with a proven track record of delivering high-quality results and with a driven commitment to ensuring a first-class student experience”.
Professor Humphris, who will take over the role in December, is the third new female vice-chancellor to be announced in recent weeks.
With the universities of Derby and Salford also appointing female vice-chancellors, it will mean, that out of 133 institutions that are members of Universities UK, 22 will be led by women.