General Motors Corp., bolstered by profitable subsidiaries and investment income, reported yesterday its highest quarterly profit in nearly four years, while Manufacturers Hanover Trust Corp., operator of the nation's fourth-largest bank, reported a 32 percent first-quarter earnings gain.

GM's net earnings of $653.1 million ($2.08 per share) compared with a profit of $128.3 million (41 cents) in the year-ago quarter. It is the largest quarterly profit for the top U.S. automaker since it earned $1.19 billion in the second quarter of 1979.

Among other reports:

* Continental Illinois Corp., whose bank is ranked number seven in the nation, said its earnings were half those of a year ago because of poor economic conditions and troublesome loans.

* Safeway Stores Inc. earned 46 cents a share in the first quarter, up from 31 cents a year ago, as sales rose to $4.219 billion from $3.984 billion and net income climbed to $23.9 million from $16.03 million. Chairman Peter A. Magowan said earnings and sales were adversely affected by foreign translation losses and that sales would have been 8.1 percent higher without the currency translation losses.

* Armco Inc. reported a net loss of $128 million for the first quarter of 1983 ($1.97), compared with earnings in the year-ago quarter of $18 million (26 cents).

* Earnings of American Telephone & Telegraph Co. for the first calendar quarter of 1983 tumbled sharply to $1.87 a share from $2.40 a year ago, when the company had 75 million fewer shares. The drop in net income to $1.74 billion from $2.01 billion occurred in spite of a rise in revenues to $16.797 billion from $15.638 billion.

GM reported factory sales of vehicles worldwide in the first three months of the year rose 21.9 percent from a year ago, to 1.79 million from 1.47 million. The company said it had record overseas sales of cars for the period, up 19 percent from a year ago.

Sales measured in dollars rose 13.7 percent, from $14.72 billion in the first quarter last year to $16.74 billion this year.

GM reported an operating income of $692.9 million in the quarter compared with a loss of $7.4 million a year ago.

The firm's subsidiaries, particularly the profitable General Motors Acceptance Corp., also added $246.9 million in earnings compared with $131.2 million in the first three months of 1982.

In a statement, GM said the "performance reflected a significant improvement in the level of profitability from operations, resulting from the strong acceptance in the market of GM's new models and continuing improvements in efficiency by GM people."

GM was the first automaker to report earnings. The other major U.S. firms are expected to report results in the next two weeks, with all of them except perhaps American Motors Corp. to be in the black.

Manufacturers Hanover, operator of Manufacturers Hanover Trust Co., said its first quarter net was $82 million ($2.04), up from $62.1 million ($1.80). The 13 percent share increase reflected dividend deduction requirements as a result of a $400 million preferred stock issue in the second and third quarters of 1982.

The company's net interest revenue was $425.8 million, up 19.4 percent from $356.5 million a year ago, attributable to a higher loan volume and a widening yield on earning assets to 3.32 percent from 2.97 percent, reflecting the greater margin between interest earned on assets and the rate paid for funds.

Manufacturers Hanover said non-performing loans were $875 million, or 1.92 percent of all loans, up from $726 million, or 1.76 percent of all loans. Assets were $59.6 billion, up from $56.9 billion a year ago.

Continental reported first-quarter net income of $31.2 million (78 cents), compared with $66.5 million net ($1.68) during the first quarter of 1982.

Net credit losses in the first quarter were $99.3 million, including $45.7 million related to Penn Square Bank participations, compared to last year's first-quarter credit losses of $22.2 million and $106.9 million in the final quarter of 1982. As of March 31, total assets for the corporation were $41.2 billion, down from $42.9 billion.

The Chicago-based holding company for Continental Illinois National Bank & Trust Co. said its non-performing credits, including $605 million of loan participations it bought from now-defunct Penn Square Bank in Oklahoma, totaled $2 billion on March 31, 1983, compared with $1.9 billion at the end of 1982.

Penn Square was shut down on July 5, 1982.