He essentially invented the modern science of endoscopy of the upper airway and esophagus, using hollow tubes with illumination (esophagoscopes and bronchoscopes).

He developed methods for removing foreign bodies from the esophagus and the airway with great safety — a huge advance for a condition that previously had often been a death sentence, with a high mortality from the object itself or from complications of chest surgery in the 19th century.

Jackson campaigned to put labels on all poisonous or corrosive substances to prevent ingestion accidents.

Accordingly, the US Congress passed the Federal Caustic Poison Act of 1927, which has saved countless children from serious injury and death.

He was elected to the American Philosophical Society in 1919 and was awarded the Franklin Institute's Elliott Cresson Medal in 1929.