Sen. Edward M. Kennedy (D-Mass.) has hired one of the most highly regarded young political organizers in the Democratic Party for his Senate staff, it was learned tonight.

Carl Wagner, 33, currently the director of political activities for the American Federation of State, County and Municipal Employes, the largest affiliate of the AFL-CIO, will join Kennedy's staff next week as a special assistant.

Wagner said he "would like to do everything I can to dispel the notion" that his hiring might signal a step toward a 1980 Kennedy presidential candidacy. But the report did cause excactly that specualtion among delegates to the Democratic mid-term conference, who had heard Kennedy deliver a rousing challenge to the Carter administration's budget policies.

Kennedy has been without a senior political aide with broad national experience and contacts since the resignation of Boston lawyer Paul Kirk from his staff about two years ago.

In Wagner, he is acquiring an organizer who has turned down several jobs in the Carter administration and whose acumen is widely admired in the liberal wing of the party.

Wagner told friends here he expected to help Kennedy organize public support for passage of a national health insurance program, but he said the frll range of his duties had not been discussed.