A surge in profitability in the fourth quarter of an otherwise mediocre fiscal year helped Garfinkel, Brooks Brothers, Miller & Rhoads, Inc., achieve its most successful year in history for the period ended Jan. 29.

The Washington retail company reported yesterday that profits for the year totaled $9.86 million ($2.25 a share), up slightly (2.3 per cent) from $9.43 million ($2.20) in the previous 12 months. Sales rose 8 per cent to a record $297 million.

Fourth-quarter profits jumped 15.3 per cent to $6.4 million ($1.50) from $5.6 million ($1.31) in the same period a year ago. Sales were up 6.3 per cent to $99 million.

President David R. Waters said yesterday that general increases in gross profit margins, "an extraordinary performance" by the nationwide Brooks Brothers chain of men's specialty stores, and "more effective" controls over inventories during the last six months of the year contributed to the higher profits.

Sales and earnings for the year reflect the openings of two new and two replacement stores. Brooks Brothers, characterized by retail sources in recent months as having the most successful period in a history that started in 1818, opened a branch in suburban Chicago and a New York City store to replace a Broadway location.

When the local Garfinckel corporation purchased Brooks in 1946, there were 3 of the men's stores; today, there are 17 from coast to coast.

Garfinckel's Richmond-based Miller & Rhoads department store division opened a store in Charlotte, N.C., last year and replaced one in Kingsport, Tenn. With these additions, the retail firm now operates 92 stores in 16 states and the District, through 6 operating divisions.

In the year ended Jan. 29, the Garfinckel corporation's income before taxes was up 11 per cent to $18 million and taxes were up 22.3 per cent to $8.4 million.

Profits were 3.3 per cent of sales in the recent years vs. 3.4 per cent in the year ended Jan. 31, 1976. In the final quarter, however, profits equalled 6.5 per cent of sales vs. 5.9 per cent a year earlier.