In the comic, Jon had attempted to ask her out on dates many times over the years, but rarely succeeded. When she did accept, the outings usually became disastrous (commonly because of Garfield coming on the date or Jon doing something embarrassing).
In 2006, whilst on a date with an amnesiac Ellen, he discovers that Liz is at the same restaurant dating someone else. After an awkward encounter with each other, Liz finally admitted that she had feelings for Jon. The two have been portrayed as a couple since, though Jon's trademark geekiness continues to both amuse and embarrass Liz.
Her first television appearance was on the second TV special, Garfield on the Town. In all animated media, she is voiced by Julie Payne. In the live-action films, she is portrayed by Jennifer Love Hewitt. In the live action films, she becomes Jon's girlfriend and later she accepts Jon's proposal of marriage. In a July 2006 storyline, shortly after the release of the second film, Liz and Jon start dating each other.
She has neatened black hair and eyelashes. Her lipstick color has changed occasionally over the years:
- From June 26th 1979 to March 21st 1981, she wore black lipstick. This was probably due to the strips being originally made in black and white.
- Her most common lipstick is red, which she first wore on August 9th 1981 to the present.
- For a single week (February 11th - February 14th 1987), she wore pink lipstick.
Over the years, she has also worn different items:
- Her casual appearance has only recently appeared and usually consists of different colored shirts, pants, sweaters and various other items.
- Her veterinary uniform was her first appearing clothing, which consists of a white working dress with short sleeves, a name tag and white shoes with white laces.
- On dates, she wears different outfits but her most common outfit is a black dress with black high heels.
- While at the beach, an inflatable pool or a water park, Liz has worn different swimsuits for those occasions. She is mostly seen wearing black bikinis. However, pink (September 4th, 2011) and red plaid (Garfield 2016 Summer Special #1) bikinis have been shown before. She has also worn one-pieces at least four times, two black (September 5th, 2010 & August 25th, 2013), one blue and white (June 12th, 2016) and one pink (Garfield Vacation Time Blues #1).
The movie version of Liz is largely different from her comic strip counterpart. Overall, she has a reddish brown bob cut, and glossy, slim red lips. Her clothes include:
- In the vet, she wears red glasses, a short beige colored dress, a veterinary jacket, a name tag and a stethoscope.
- Her pet show outfit consists of a pink jacket, a short red dress, red high heels and a red clutch.
- While looking for Garfield and Odie, Liz wears a short white dress, white high heels, and a shortened cloak.
- At the end, she wears a pink and white sweater, white pants and flat white shoes.
At the start of the second film, her hair is shown to be a darker brown, and is curlier than usual.
- At Arbuckle's house, she wears a white dress with red markings, a black line on the front of it, and an uncovered back.
- When in the hotel room, she wears a dark gray jacket, pink pants, and dark gray running shoes with shoelaces.
- In the pub, she wears a yellow t-shirt, a dark red jacket, and jeans.
- At Carlyle Castle, Liz has her hair in a bun, wears a long blue dress with no sleeves, a bracelet, and white flat shoes.
Her television look is very similar to her comics except, at the time, only her top lip is shown. Her veterinary and date outfits are almost the same as well.
In The Garfield Show, she, again, looks very similar to her comics counterpart. Her veterinary uniform's only changes are:
- Blue shoes
- A blue watch.
Her date outfit is the same excluding:
- A golden watch.
- The white line at the bottom of her high heels.
She can be sarcastic and smart-mouthed but is also sweet, kind, caring, and animal-loving.
She has a somewhat deadpan and sardonic persona, played up more in the years before she and Jon began dating. Liz would constantly shut him down with effortless sarcastic responses to his lousy come-ons. She would occasionally take pity on him and go on a date with him, although she usually expressed low expectations. After becoming his full-time girlfriend, Liz continues to maintain her stoic personality, but balances this with her best attempts to be supportive of Jon. Liz is rarely exasperated by Jon's outlandish and goofball behavior, even finding it endearing.
Originally, Liz treated Garfield as a simple patient and did not show much of an interest around him. When she became Jon's girlfriend, Liz attempted to make peace with Garfield, but he was initially jealous of Liz as he felt that she was moving in on their lifestyle. Garfield eventually warmed up to her presence (with help from a few peace offerings of pizza) and now tolerates Liz at a bare minimum.
The movie version of Liz is shown to be completely unlike her comic strip counterpart, as she is more of a sweet and kindhearted person, rather than her sarcastic and deadpan persona in the comics. She displays a love for animals, as she shows much concern over Odie. She also has a crush on Jon, as they went to school together, though in the strip she gets to like him over time.
- Jon, the prototype version of what became Garfield, depicted a prototype of Liz that slowly evolves closer to her Garfield persona.
- Her first appearance in a strip was February 26, 1976. She looks completely different from her current appearance, having blonde hair and no makeup. Jon would pursue her around town at random after this, constantly getting blown off or intimidated by a large man that was likely her unnamed boyfriend. She had no name for most of her early appearances, only referred to as "That girl" by Jon.
- By Liz's third appearance on September 23, 1976, she had adopted the basic look she would have for Garfield proper of black hair, a tired sarcastic expression, and black upper lip.
- On March 3, 1977, Irma reveals she has hired a new waitress that is revealed to be Liz, though her actual name is not given until the next week's strip, where Jon asks her if "Liz" is short for "Elizabeth" and she sarcastically responds it is short for "Lizard." The latter strip's dialog would be recycled (albeit in the context of the veterinarian's office) for the syndicated Garfield strip on June 27th 1979. Liz's remaining appearances would continue in the context of the diner.
- Notably Liz never appears with Garfield during the original strip's run. Her job may have changed to veterinarian in the syndicated version to justify having Garfield present during her appearances with Jon.
- Originally, Liz's birthday was around July 20th. Later comics appear to give her birthday as either the 12th or 13th of January.
- On December 1st 2006, it is revealed her private car is a green Volkswagen New Beetle. She had a silver Nissan Frontier in the movie, but now has a gray GMC Canyon.
- She is the 4th-most frequently appearing character, after Garfield (1st), Jon (2nd) and Odie (3rd). Liz started appearing much more frequently in the comics after she and Jon started dating and became an official couple.
- On March 5th, 2011, Jon revealed that Liz's nose twitches when she is angry.
- "Return of the Buddy Bears" (mentioned)
- "King Nermal" (mentioned)
- "Odie in Love" (mentioned)
- "Nice to Nermal" (mentioned)
- "Up a Tree" (mentioned)
- "Turkey Trouble"
- "Meet the Parents"
- "High Scale"
- "Curse Of The Cat People"
- "Fame Fatale"
- "Fish to Fry"
- "Little Yellow Riding Hood"
- "Family Picture"
- "The Last Word"
- "Home for the Holidays"
- "The Spy Who Fed Me"
- "Dog Days"
- "With Four You Get Pizza"
- "Fido Food Feline"
- "Great Pizza Race"
- "A Gripping Tale"
- "Wicked Wishes"
- "Rain or Shine"
- "Furry Tales"
- "Laugh in a Can"
- "Bath Day" (mentioned)
- "Partners In Mime"
- "Long Lost Lyman"
- "Online Arbuckle"
- "Every Witch Way"
- "Revenge of the Cat People"
- "Filthy Fugitives"
- "Take a Ferret to Lunch"
- "Lion Queen"
- "The Mean Machine"
- "Against All Tides"
- "Mother Owl"
- "Garfception" (dream sequence)
- "Home Sweet Home"
- "Delicious Donut Day" (mentioned)
- "Jon 2"
- "World Without Me"