Jim Nathanson, a teacher at the Duke Ellington School of the Arts and a Democratic Party activist, launched his campaign yesterday for the D.C. City Council seat being vacated by council member Polly Shackleton (D-Ward 3), calling for more school funding and preservation of park space.

"The City Council should give the superintendent of schools every penny she feels she needs," Nathanson said to a gathering of about a dozen supporters. Mayor Marion Barry's latest budget proposal for fiscal 1987 does not fund the school board's full request.

Nathanson, 53, spoke at the Glover Archbold Park, near Wisconsin Avenue and Van Ness Street NW, where he opposed permits granted to the Donohoe Co. to build a road into the park. He said the road, if built, should not take up as much of the open space as now planned.

Two other announced candidates for the Democratic nomination for the Ward 3 seat -- political consultant Mark Plotkin and newsletter publisher Ruth Dixon -- have made development in the ward an issue.

Plotkin has said that, if given the chance, developers would turn Ward 3 into another Rosslyn or Crystal City. He has supported designating the Cleveland Park neighborhood as a historic district to limit development. Dixon has said that "we're rightly concerned" about commercial development but that it's inevitable and its impact on communities should be minimized.

Nathanson said it's important to recognize "that development will come" and said that efforts should be concentrated on harmonizing development along Wisconsin and Connecticut avenues with the surrounding neighborhoods.

Shackleton, who earlier had endorsed Nathanson for the seat, attended the gathering and brought with her a list of successful candidates she has supported in the past, countering the suggestion by some that she has mainly backed losers. On the list were Barry in his school board and mayoral campaigns, Walter E. Fauntroy in his campaigns for D.C. delegate to Congress and Arrington Dixon in his first race for City Council chairman.

Nathanson has practiced law and taught at D.C. public schools, including Cardozo High School. He graduated from Harvard University and received both a master's degree in education and a law degree from George Washington University.

Others mentioned as possible candidates for the seat include Democrat Mary Draper Janney, a former leader of Wider Opportunities for Women and Planned Parenthood of Metropolitan Washington, and Republican Gloria R. Corn, an advisory neighborhood commissioner and Forest Hills resident.