The transit system, which shuttles thousands of visitors around the sprawling resort each day, was shut down while authorities investigated the holiday weekend wreck.
The monorail operator died at the scene of the crash, which happened around 2am local time, said Bo Jones, deputy chief for Reedy Creek Fire Department.
The other train operator was uninjured, but was taken to a hospital because he was emotionally shaken. Jones said five park guests were treated at the scene, though the Orange County Sheriff's Office said six were treated.
Disney vice president of communications Michael Griffin identified the driver as 21-year-old Austin Wuennenberg. Griffin would not discuss how long Wuennenberg had been with Disney or the circumstances surrounding the crash. Disney officials also refused to talk about how the monorail system operates.
"They are extremely rare," Griffin said of accidents at the park. "The safety of our guests and cast are a top priority above all else." It is unclear what caused the crash, Jones said. Orange County Sheriff's officials are investigating.
A spokeswoman for Stetson University in nearby DeLand confirmed that Wuennenberg was a student at the school. A woman standing in front of Wuennenberg's home in Kissimmee declined comment Sunday afternoon and directed all questions to Disney officials, saying the family would "like some private time to grieve."
Jones said the crash happened at the park's ticket and transportation center. About a dozen guards wearing blue Disney security uniforms guarded the monorail station Sunday morning and prevented visitors from approaching the area.
Griffin would not comment on a video posted on the Web site of Orlando TV station WKMG. The clip, apparently shot by a guest at the theme park, shows several people trying to get the driver's attention as they examine the wreckage.
"This is such a close-knit community, " Griffin said. "Our hearts go out to Austin's family. It's a sad day here." Catherine McKenna, 45, and her family were visiting the theme park from Ireland. The family had planned to use the monorail to travel to the Magic Kingdom but said they were told the train was broken. They took a ferry instead, but returned on the monorail later.
"It's very sad," McKenna said. "You would be very afraid to use it again." However, another guest, 55-year-old Jose Sequera of Venezuela, said he was not concerned about safety at the park.
"I think they take care of things," Sequera said. "Accidents happen, the same as in planes and cars." Disney spokeswoman Zoraya Suarez said the park had boosted other forms of transportation -- such as ferry, boats and buses -- for visitors Sunday.
"Our guests are getting around fine," Suarez said.
Griffin issued a statement offering condolences to the employee's family and saying the monorail was closed.
"It's a bit shocking," said 22-year-old Danielle Williams, of London. "Disney seems so perfect."
