The company earned $1.25 billion, or $1.09 per share, up 1 percent from $1.24 billion, or $1.03 per share, a year earlier.
Total revenue, net of interest expense, was $7.86 billion, up 4 percent from a year earlier. Revenue grew at the slowest rate in 11 quarters.
The company's American cardholders, mostly affluent consumers, reined in their spending.
Cardmember spending in the United States rose 8 percent in the quarter. That figure, though up from the second quarter, is still below the double-digit growth the company had posted for the nine preceding quarters.
"It represents slower growth than we were generating earlier in the year, a trend that we are seeing among major card issuers," Chief Executive Kenneth Chenault said in a statement.
The company has the lowest delinquency rate among the large credit card companies, including JPMorgan Chase , Discover Financial , Capital One , Bank of America and Citigroup .
But it set aside $479 million to cover future bad loans, reflecting its larger lending portfolio, 92 percent more than it provisioned last year.
"We didn't have the same benefit from substantial reserve releases as last year when write-offs and delinquencies were declining at a faster rate," Chenault said.
American Express, which lends directly to consumers and also competes with Visa Inc and MasterCard Inc to process credit card transactions, said global network and merchant services revenue grew 5 percent to $1.3 billion.
Shares of the company, which have risen more than 24 percent so far this year, closed at $59.37 on Wednesday on the New York Stock Exchange.
(Reporting by Jochelle Mendonca in Bangalore Editing by Supriya Kurane)