The fight happened at the McDonald's on 2nd and Colorado streets around 5 a.m., according to the witness who recorded the incident.
The witness said fights happen often at the location and many homeless people sleep in the area.
The fight the person recorded involved customers who were drinking beer inside the restaurant but who had not purchased food, according to the witness. They said the security guard went up to the group, asking them to leave because they were loitering.
A fight broke out, with a man repeatedly punching the security guard. It appeared some people tried to stop the fight, but the men continued to pummel the guard.
At one point, a man is seen using a chair to hit one of the men fighting the guard and they end up falling through the front doors into the parking lot.
Police eventually arrived to break up the fight. One man, described as a transient who lives in the area, was arrested for felony assault with a deadly weapon. Police are continuing to investigate to see if charges will be brought against anyone else.
Authorities acknowledge the restaurant is a site for frequent problems and they try to provide a police presence in the area.