The oldest buildings, in the first quadrangle, date from the 16th and early 17th centuries; a second quadrangle was added between about 1640 and about 1713, and a third quadrangle was built in about 1906. In 2022, the college opens the Cheng Yu Tung Building on the corner of Cornmarket and Market Street, providing a fourth quadrangle, new graduate accommodation, teaching spaces and a Digital Hub. In addition there will be a new café and exhibition galleries.

Jesus still has a particular association with Wales and is often referred to as "the Welsh college". The college is home to the University's Professor of Celtic, and a specialist Celtic library, in addition to the college's 17th Century Fellow’s Library and normal library. It is now also home to a global community of students and Fellows, including many world-leading academic researchers in subjects as broad as climate science and medical research, law and classics. It’s Welsh roots come to the fore most prominently on St David's Day (March 1st) when the college is decorated with daffodils, a Welsh tea is served in the Elizabethan hall and a special choral Evensong is held in the chapel.