The font is "intelligent." It automatically adjusts tracking (the space between letters) and bashline alignment depending on the point size to ensure it is readable from the back of a large auditorium.
Apple doesn't use just one version of San Francisco in its keynotes. They use a carefully layered hierarchy: what font does apple use in their keynote presentations
The query is to designers and brand enthusiasts. However, the answer is slightly more complex than a single font name. The results for this query will almost certainly center on San Francisco , but a thorough review must distinguish between Apple’s system font and the specific Keynote application defaults. The font is "intelligent
Helvetica is the infrastructure of the tech world. It is neutral, ubiquitous, and safe. By using Helvetica Neue for smaller details or UI demonstrations, Apple grounds the futuristic Avenir headlines in a reality that users recognize. It suggests: "This is futuristic technology, but it works just like the reliable tools you already know." However, the answer is slightly more complex than
It is a "neo-grotesque" sans-serif, similar in feel to Helvetica but with a taller x-height (the height of lowercase letters), making it easier to read from the back of a large auditorium.
While these fonts are free for developers to use on Apple platforms, they are not licensed for general use on non-Apple systems like Windows or Android. Historical Fonts Used in Apple Keynotes