At Torcon 2, the 31st World Science Fiction Convention (or "WorldCon"), held in 1973 in Toronto, the only security force was hired security guards. There was friction between the guards and the fans. The guards did not understand the fannish milieu. One miscreant fan stole one of noted illustrator Kelly Freas's paintings from the Art Show. The story goes that he showed the rental guard at the door a receipt for a piece of much lower value. The guard didn't know any better and let him through.

However it happened, it left a lot of people upset and worried about what was happening in the science fiction fan community.

Fandom was changing. There were large influxes of new fans brought in by Star Trek and other media interests. Conventions were getting bigger. They were no longer the small, clubby get-togethers of the '50s and '60s. Although there were loud outcries that "Fans don't steal from fans" the fact of the matter was that things had changed.

Robert Asprin realized the need for a corps of experienced fans who could provide security, crowd control, guest escort and other services to conventions, and with knowledge of the norms and customs of fandom, could, in theory, provide these services without the hostility and conflict caused by a clash of cultures between the mundane world and the fannish.

Asprin was an admirer of the work of Gordon R. Dickson and he asked and received permission from Gordy to use the name "Dorsai Irregulars" for the organization.

Next year the WorldCon. Discon II, was in Washington D.C. Asprin and six other fans in green uniforms and berets appeared on the masquerade stage and made a light-hearted attempt at some close-order drill. Then Asprin took the mic and announced that the Dorsai Irregulars were available for duty.

That was the start of the Dorsai Irregulars.
After its initial appearance, contracts flew in. And with more work, the need for members also increased and the numbers grew to about 24. Dorsai contracted for security at a variety of SF and media cons and the group's fame, reputation and mythology grew.

Since most members were in their early 20s, it was easy to cultivate a gung-ho, go-anywhere style. During this time the Klingon Diplomatic Corps provided an alter ego for the DI.

Eventually Bob Asprin left the group; the Seventies waned, and the paramilitary look was discarded. Around this time the DI also started holding their own small, annual relaxacon, Thing, near St. Patrick's day.

As the group aged and moved from being college students to "adults" demands of family and jobs caused a slow period but by the late 1980s, the DI had started inducting some new, younger members. Soon these younger members re-energized the group and Dorsai were seen again working at 6 to 12 conventions every year. Now the DI number over 100 active members and have settled into a pattern of continuous slow growth. Since their children now number over 50, it's a matter of survival. Dorsai Thing has continued through the whole time. In 2024, it will have been held in 49 consecutive years in more than 20 cities.