Always use the first and last name of a person on first reference. Use the last name only on subsequent references, unless needed for clarity (for instance, quoting multiple members of a family with the same last name).
Example: John Smith visited Ivey in May. Smith (not John) spoke with students about his experiences at Google.
In notes to the Ivey community, use the full name on first reference, and the first name on subsequent references.
Example: I am pleased to welcome Professor Angela Baxter to Ivey. Angela previously worked at Thunderbird School of Global Management.