He moved to the United States where he served as a professor of pathology at the University of Michigan, Ann Arbor.

Gibbes was born in Berrow, Somerset, where his namesake father was a minister while his mother Margaretta was the daughter of John Murray, an admiral in the Royal Navy.

His paternal great-grandfather, Sir George Smith Gibbes (1771–1851) was physician extraordinary to Queen Charlotte while his maternal grandfather John Murray was an Admiral in the Royal Navy.

He became a licentiate of the Royal College of Physicians in 1879 and in 1887 he became Professor of Physiology and Normal and Morbid Histology at Westminster Hospital Medical School.

During his tenure at Michigan, he often held out-dated theories of disease causation despite considerable advances in bacteriology.