Guardian is a calm level headed figure of authority. Unlike his employer, Dr. Desmond, he tends to be a bit more open minded on certain issues and will seek a peaceful resolution if possible. This annoys Desmond to no end and he often has to use Guardian's G-Gnome to make him see things his way instead.
Guardian is a strongly built Caucasian male with red hair and blue eyes. He strongly resembles his "nephew", Red Arrow. During his time as Guardian, he wore a dark blue jump suit with a golden helmet and golden shoulder and wrist pads.
Jim Harper was cloned by Cadmusfrom the original Roy Harper. Although he was the younger clone chronologically, he was force-grown to be physically older than Red Arrow.He was implanted with false memories that he was the grandson of the original Guardian, also named Jim Harper.
He officially joined Cadmus as head of security in 2009. Guardian was already a figure of some notoriety before joining Cadmus.
Guardian investigated a small fire on at ground level, and after notifications from genomorphs, he found three intruders: Robin, Aqualad and Kid Flash. He tried to make them leave peacefully, but when Kid Flash mentioned the weapons made in the facility—something Guardian seemed unaware about—his G-Gnome made him attack them. They fled, and eventually locked themselves in with Project Kr. They released the Superboy, but the clone's programming turned against them. They were quickly defeated.
With the sidekicks in containment pods, Guardian saw no need to return Superboy to his pod immediately. Desmond disagreed, and used the G-Gnomes to sway Guardian. But on his way back, Superboy rebelled and broke the sidekicks out. Guardian and the genomorphs chased them.
At the ground level, Dubbilex revealed that he was behind the events set in motion the previous day, so Superboy could be free. He lifted the telepathic control on Guardian, who vowed to deal with Desmond whilst the other exposed Cadmus. But Desmond would not go without a fight. He ingested Project Blockbuster, and in his new, monstrous form, knocked Guardian out.
Later, The Cadmus Board of Directors appointed him as the new head at their DC branch. On his first day, Guardian appointed Dr. Spence as acting chief scientist and declared that no more G-Gnomes would be used to suppress wills nor would there be any more secret breeding projects, and that he would usher in a new "kinder, gentler Cadmus".
Guardian had his hands full searching for missing genomorphs. Over the past months, many genomorphs had disappeared. Dubbilex promised to help him, but there were no results.
When Superboy demanded entrance into Cadmus, Spence tried to dissuade Guardian from actually letting him in. Guardian did so anyway, and welcomed Superboy with open arms. Superboy inquired about another super-clone, but Guardian knew nothing of it. Instead, he gave a tour to show the new and improved Cadmus, where scientists and genomorphs worked side by side on medical research. During this tour, Superboy learned that Guardian was the uncle of Roy Harper.
Guardian was shocked when Superboy uncovered Project Match, and denied any involvement on his part, or Dr. Spence's.
The fight that broke out between Superboy and Match lead to a secret underground city created by Dubbilex. Guardian stopped Superboy from completely destroying Match, and prepared to have all of Dubbilex's secreted genomorphs placed back with Cadmus.
Jim Harper found out that he himself was a Cadmus clone. After getting a mental scan from both Martian Manhunter and Miss Martian to ensure no trace of Cadmus programming remained inside his mind, he gave up his position at Cadmus, as well as the Guardian suit and identity.
In the comics, Guardian is Jim Harper, a Golden Age hero who is cloned many times by the Cadmus DNA Project since the 1970s. He was later (in 1977) revealed to be Roy Harper's uncle (the older brother of Roy's father Will). As the gap between the war and the present day got larger, Guardian was retconned into a great-uncle instead in 2001.