He first appeared on August 7, 1978. He was only actively present for a few months after his debut appearance. Starting from 1981, he was usually absent; for instance, he did not appear in any strips between December 25, 1981, and June 27, 1982. He had largely disappeared from the comic by April 24, 1983, his last regular appearance, and his disappearance was not fully elaborated upon at the time. Lyman has made two cameo appearances in the comic since then. First, in the strip on Garfield's 10th birthday, June 19, 1988, where he appears in the title panel seated between Jon's father and Liz; he also appears in a flashback panel within the strip. The next was on April 2, 2013, in a picture on the newspaper Jon was reading.
According to Davis, Lyman's original purpose was to be someone who Jon could actually talk to and express other ideas — a role gradually taken over by Garfield, himself. Once Lyman was no longer needed for that purpose, he was removed without explanation. Jim Davis has jokingly given explanations about Lyman's sudden disappearance and long absence from the strip; examples include Lyman joining the Peace Corps and never being heard from again and "Don't look in Jon's basement."
In the web game "Scary Scavenger Hunt," he is shown chained onto the wall in the basement of a haunted mansion. In "Scary Scavenger Hunt 2," his head is found inside the kitchen oven. Also, on the official Garfield website, he was shown working behind the counter in a former edition of the "Book Nook" section.
After decades of absence, Lyman made his big comeback in the Garfield Show story arc, “Long Lost Lyman". In this arc, it is revealed that he was a wild life photographer. He had gone to Australia and searched for a mythological creature, but suddenly disappeared without a trace. When Jon, Garfield and Odie went looking for him, they had found him dressed as that creature. Lyman explained that he never contacted them, because there was no way he could. Lyman decided to stay in the jungle to protect the wildlife from poachers, but does promise to visit whenever he can.
- Lyman has appeared 69 times in comics, the 24th most.
- Lyman’s last regular appearance was in 1983.
- Lyman grew up with four cats, all named Cat.
- In The Garfield Show, instead of having dotted eyes, he has regular eyes like Garfield and most other characters (likewise with Mom Arbuckle).
- Lyman, in one strip, appears to not care about his appearance, as when asked by Jon Arbuckle for an opinion on something to wear, Lyman is wearing an assortment of mismatching clothing.
- In the book 20 Years and Still Kicking!: Garfield's Twentieth Anniversary Collection, one of the sections is named Top Ten Explanations For Lyman's Disappearance and includes:
- 10: Left strip to pursue dream of Olympic figure-skating gold.
- 9: Joined CIA, working undercover in Russian comics.
- 8: Had lunch with Jimmy Hoffa, and then...
- 7: Took role as Elaine on "Taxi".
- 6: Hit on Blondie and Cathy; editors complained; Davis fired him.
- 5: Disfigured in drawing accident.
- 4: Moved to San Francisco.
- 3: Opted for career in Hotel/Motel management.
- 2: Ballooned to 270 pounds; wouldn't fit in cartoon panels.
- 1: Don't look in Jon's basement!
- In a "Comics: Meet the Artist" discussion with Jim Davis on The Washington Post, two readers asked about Lyman's disappearance. Davis responded to each:
- Long Lost Lyman
Lyman's mysterious disappearance from the strip is discussed at Neatorama.com.