Erickson was voiced by James Doohan.
In the script of "Yesteryear", Erickson was described as "a small, intense man."
According to both the novelization of "Yesteryear" (in Star Trek Log 1) and The Four Years War, role-playing games sourcebook, this character's first name was Ted. Also in the novelization, Erickson is actually a Federation historian, similar to Grey and Aleek-Om, and is in his mid-forties.
The novels Provenance of Shadows and The Fire and the Rose switch the roles of Erickson and Bates, so that Bates accompanies Kirk and Spock through the Guardian, while Erickson stays on the ship and researches Spock's history. This switch happened because both characters' names are not mentioned in dialogue, so the author was unable to determine which was which and ended up making the wrong guess.