Other than that he grew up to become a Police Chief, nothing is known of Clark's past.
Chief Clark made his debut in the film informing Detective David Madison that the breed of dog found near a human victim's body was a rare breed, with only three registered in the entire state. Later, after the discovery of another human victim, Clark called Madison in to a press conference, trying to help ease the event when Madison ended up storming out. After Madison had gone into the sewers and been hospitalized after supposedly being attacked by a giant alligator, which took his partner, Clark appeared at the hospital and tried to convince Madison to take some time of, to no effect. After Thomas Kemp, a rival of Madison's in the new reporting area, arrived, the two gave him no information and left to go and see Dr. Marisa Kendall, a herpetologist. for advice about alligators. She stated that no alligator could survive in the sewers and told Clark there was no animal she could think of possibly in there when he asked. He thanked her, and drove Madison away, informing him that Kemp was out to get him. After Kemp's camera was discovered in the sewers, Clark was stunned to see photos of a giant alligator, which he stated that they should let Kendall see. After Madison began to mount an operation to kill the alligator, Clark introduced him to the mayor and explained to him when Kendall arrived that she might be able to help predict the alligator's movements. Later, after the operation failed, Clark left with Madison to figure out how to explain it to the press, telling reporters there would be a press conference the following morning. However, the alligator smashes through concrete and nearly killed a police officer, before disappearing. Clark angrily reprimanded Madison, before Kendall informed them that the beast would head for water after using so much power. While talking to the mayor, Clark reminded him that the safety of the public was his job, before ignoring his senseless complaints.
The next day, Chief Clark and the mayor introduced Madison to Colonel Brock, a professional big-game hunter and tracker with world-wide success, who had been flown in and hired to kill the alligator, resting control over the hunt from Madison. Clark explained that it was for the best, as now it was a whole new ballgame, and introduced Brock to Kendall. Driving Brock to a recent location of the alligator, Clark was shown a huge pile of dropping from the best by Brock. Later, at the police station, Clark reluctantly fired Madison, who had discovered Slade Pharmaceudical, a company owned by a powerful friend of the mayor, was responsible for the alligator's giant size(30 to 40 feet) and ravenous temper, after recieving a phone call from the mayor, who had been tipped off by Slade. After Brock was killed and the operation began to fall apart, Clark angrily refused to talk to Madison, before later being informed later that the alligator was in the canal. After arriving at Slade mansion, where the alligator had killed several, he begged Madison when he saw him running for, only to be seemingly ignored(in fact Madison and Kendall were heading to kill the alligator with a bomb). After they did, Clark arrived and was relieved to see Madison alive, stating he never doubted him and being humored at his remark about locking him up with Kendall's mother.
Chief Clark took his job very seriously, but was easily upset and frustrated, which tended to cause him to be disrespectful to others sometimes. Clark was, however, respectful most of the time to others. He did, however, have a sense of humor. He did not appear fond of the mayor, who was very selfish and annoying.
Chief Clark, given the long time he held the job, was very skilled at his work and, despite his being easily angered and frustrated, showed to be a capable leader.