https://disney.fandom.com/wiki/Tom_Fitzgerald
He had just joined WED the same year he sent that reply (1979). Worked there until 2020 in various leadership roles. Seems to have been particularly involved in the making of EPCOT.
A web search shows all kinds of interesting interviews etc.
He sent the letter in April 1979! He was only 3 months into the job.
Classic, have the new guy deal with the fan mail.
He still works at WDI.
Nice!