The job-seeker, a former social services administrator out of work since a year ago last June, stared into the television camera. He had 40 seconds to make his employment pitch.

"Hello. My name is John Dundas," he said, pausing nervously before giving a brief employment history. "I'm 52 years of age. I'm strong, vigorous and ready to go to work."

Tonight, Dundas and a dozen other out-of-work Washington area residents will deliver "Hire Me" spots on a "Job Fair" broadcast on Channel 20 (WDCA-TV). The program, to be broadcast from 8 p.m. to 10 p.m., also will feature tips on job hunting and retraining, phone calls from employers pledging jobs and employes seeking them (a computer will match them up) and taped and live personal appeals for work.

The sign-of-the-times show is the first of its kind in this area, but similar televised job-a-thons have been held in Columbus, Des Moines, Louisville, Milwaukee and Wheeling.

One is planned for Boston; a San Francisco station makes "Hire Me" spots a regular feature of its newscasts, and some newspapers have offered free employment-wanted ads.

"The number one problem in our community, as it is everywhere, is unemployment," said Farrell Meisel, Channel 20's program manager. "This is truly what local television should be doing."

Meisel says Taft Broadcasting Co., which owns Channel 20 and six other stations, decided an on-air job fair would be a good project, especially after its Columbus station held one in September and placed more than 500 job-seekers.

Taft's stations in Cincinnati, Kansas City, Birmingham and Buffalo will also air similar programs tonight. Channel 20 has coordinated its efforts with Maryland, Virginia and District of Columbia employment offices and is picking up the tab on computer, phone bank and filming costs, worth well over $20,000, according to the station.

President Reagan has given the program a boost by taping promotional spots and an appeal for private sector employers to hire the jobless. D.C. Mayor Marion Barry also has taped a jobs appeal for the program, and Govs. Harry Hughes of Maryland and Charles Robb of Virginia have endorsed it.

Another job hunter who will appear on the show is Therman Coles, 35, a Vietnam veteran who said, "I've seen it from the other side of the counter, and now I'm seeing it from this side of the counter." Coles was a program director for job-placement training, counseling others on how to make a good impression at interviews until last August when he lost his job after government CETA regulations were rewritten, making it harder for his employer to get funds.

"I never thought I'd be in this situation myself," said Coles, a Silver Spring resident who has two daughters, 18 and 12. Like Dundas, he taped a "Hire Me" spot for the show at the Maryland Employment Security Administration's Wheaton Plaza office this week.

"I have a B.A. in political science, a law degree from Howard University and am completing work, hopefully by June, on an MBA," said Coles.

Dundas, who lives in the Rockville area and is the father of two, ages 11 and 20, is experiencing unemployment for the first time since he graduated from high school. A Korean War veteran with a degree in psychology, and nearing a master's in sociology, he's finding it hard to find work in his social services field.

Not everyone featured on the program will be unemployed. Alexandra Pantelides, 22, of Annapolis, has two jobs, as a waitress and clerical assistant, both a far cry from the personnel career she hoped for last June when she graduated from college with honors.

"I'm told it's hard to find a job in personnel with so little experience," she said. "I wish more people were willing to give graduates a chance."

Also taping spots for the show were Norm Kaufman, regional director for operations for Hardee's Food Systems; Jack Hix, recruiting manager for Tracor, Inc., which does defense contracting for the Navy; and Angelita Moreno, personnel director for Applied Management Sciences. Hardee's is looking for assistant managers. Tracor has 200 to 300 openings for electronic, electric and mechanical engineers. Applied Sciences has 25 openings for economists, statisticians, clerks and secretaries.

With their help and job pledges from other employers, the program will be trying to make a small dent in the region's unemployment. For Dundas and others, that's reason enough to hope.

"I'm going to go to work, somehow, someway . . . soon," he says.