He studied medicine at Aberdeen University, where he qualified in 1878 and obtained his M.D.

[4] He lectured on it in Europe and America, often using his dog Jimmy in his ECG demonstrations.

However, eventually other physiologists such as Willem Einthoven and Thomas Lewis showed Waller that the traces could help diagnose heart conditions.

In 1917, a few years before his death, Waller published a study of over 2000 traces of heart conditions.

[6] He was appointed Fullerian Professor of Physiology in 1896 with a starting date of 13 January 1897.