Samuel J. Simmons is a pleasant fellow who often seems ready to frown, a tendency that reflects his serious dedication to his job as president of the National Center for Housing Management.

Formerly with the Department of Housing and Urban Development, Simmons has headed the non-profit, federally mandated agency since it was set up five years ago to find solutions for the high failure rate of federally subsidized housing.

Unlike some black appointees who quit the Nixon administration, Simmons, assistant HUD secretary for equal opportunity in housing, had no harsh words when he left the agency. He caled his new job "a step up" and said he had "no criticism whatever of what we were able to do" to promote equal opportunity in housing.

Simmons and his 16-member staff work to raise the level of professional competency in the management of federally backed housing.

"It hasn't been easy and it's been full of frustrations," he acknowledged the other day. "But we keep trying to raise the level of professional training and guidance for the managers" who oversee the housing for many of America's poorest most beleaguered families.

Simmons is quick to point out that many of the problems confronting these managers are economic and social.

"I'd have to put the economic aspect first because it affects both the residents and the buildings in which they live," he said. "The income of residents has not kept pace with the increased costs of taxes, operating expenses, insurance, utilities and all other services. Nor has the income being generated by the buildings - many because increased subsidies have been granted only for taxes and utilities."

Simmons says the main problem of any federally subsidied rental building is "cash flow." He adds that all the costs of operation, some stemming from construction shortcomings, are overwhelming and present a constant struggle "just to keep the project from going into foreclosure."

Insurance for such projects is also increasingly expensive and hard to obtain, he said, while finding competent help to perform menial chores is tough because o f the relatively low pay scale.

"Finally, if you want to look at realities, you have to recognize that many of thes projects are the repository for all of our social ills - unemployment, drugs and all the rest," he said.

Because managing subsidized housing not exactly a sinecure, with pay scales set below those for private management (which aren't high), the National Center for Housing management has devised training aids, conferences and programs to raise the level of performance and the morale of the managers.

Simmons has also set up an Affiliated Council of Managing Agents, an advisory group consisting of 36 persons who manage 16 per cent of the federal housing supply.

After talking for nearly an hour about efforts to better the lot of the millions of persons living in federally supported housing and jobs of the people who run the projects, Simmons stated that the U.S. really has a responsibility to provide the money to save its subsidized projects.

The NCHM executive added that he has been disappointed by the failure of the current administration's Office of Budget and Management to provide more financial help.

"There's change in the rhetoric and more sensitive, sympathetic attitude - but no more action," he commented. Simmons said more money is needed to provide and maintain subsidized housing. Standards of performance must be improved, he said, and a plan needs to be established for more coherent community development in cities.

One view of how Simmons has been doing his job came from Lester P. Condon, the chairman of NCHM board of directors (and executive vice president of the Federal National Mortgage Association).

"NCHM would never have survived without him because he's highly knowledgeable in the housing field," Condon said.

Another person in the housing field described Simmons as dedicated and intelligent - "a leader in a fragmented field that needs his leadershop."

Although he drinks his share of coffee and whiffs his share of cigarettes, Simmons manages to stay fairly fit at 50. He says he finds no time for leaf raking and grass cutting at his home in Shepherd Park. He and his wife have two grown sons.

SImmons has no hobbies but in his spare time is president of a volunteer group seeking to provide better housing for aged black persons. The group hopes to break ground for a project here next year, he said.