Exhibit 99.1

S&T Bancorp, Inc. Announces Fourth Quarter and Full Year 2014

Results and Declares Quarterly Dividend

Indiana, Pennsylvania – January 27, 2015 – S&T Bancorp, Inc. (S&T) (NASDAQ: STBA) has announced its fourth quarter and full year 2014 earnings. Fourth quarter earnings were $14.5 million, or $0.49 per diluted share, compared to third quarter of 2014 earnings of $14.7 million, or $0.49 per diluted share, and fourth quarter of 2013 earnings of $11.9 million, or $0.40 per diluted share. Full year 2014 earnings increased 15% to $57.9 million, or $1.95 per diluted share, compared to 2013 earnings of $50.5 million, or $1.70 per diluted share.

Highlights:

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S&T Earnings Release –2

S&T Bancorp, Inc. Announces Fourth Quarter and Full Year 2014

Results and Declares Fourth Quarter Dividend

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“We are extremely pleased to report a 15% increase in our earnings for 2014 which was driven by solid loan growth, a stable net interest margin, well controlled expenses and excellent asset quality.” said Todd Brice, president and chief executive officer of S&T. “The execution of our growth strategy continues with the announcement of our merger with Integrity Bancshares, Inc. in south-central Pennsylvania and our planned market expansion into western New York. We are well positioned to build upon the momentum that we are experiencing into 2015.”

Net Interest Income

Net interest income increased $0.5 million to $38.1 million compared to $37.5 million in the prior quarter. Net interest margin on a fully taxable equivalent basis (FTE) decreased to 3.43% compared to 3.50% in the third quarter of 2014. Net interest margin was impacted by lower loan rates during the fourth quarter and slightly higher deposit costs. Loan rates declined 4 basis points to 3.98% compared to 4.02% in the third quarter of 2014. Despite the lower net interest margin rate, net interest income increased due to average loan growth of $89.5 million, or 2.4%, from the third quarter of 2014.

Asset Quality

Total nonperforming loans decreased to $12.5 million, or 0.32% of total loans at December 31, 2014 compared to $13.5 million, or 0.35% of total loans at September 30, 2014. Net charge-offs for the fourth quarter of 2014 were $0.5 million compared to net charge-offs of $0.7 million in the third quarter of 2014. The provision for loan losses was $1.1 million in the fourth quarter of 2014 compared to $1.5 million in the third quarter of 2014. The allowance for loan losses was $47.9 million, or 1.24% of total loans, compared to $47.3 million, or 1.24% of total loans, at September 30, 2014.

Noninterest Income and Expense

Noninterest income decreased $0.7 million to $11.2 million compared to $11.9 million in the third quarter of 2014. The decrease in noninterest income was primarily due to

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S&T Earnings Release –3

S&T Bancorp, Inc. Announces Fourth Quarter and Full Year 2014

Results and Declares Fourth Quarter Dividend

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seasonality in our insurance and merchant businesses. Noninterest expense increased $1.3 million to $29.7 million compared to $28.4 million in the third quarter of 2014. The increase was mainly due to merger related expenses of $0.7 million, a $0.3 million increase in professional services and legal related to a consulting project and a $0.5 million increase in other expense primarily related to a contract termination fee.

2014 Full Year Results

Full year 2014 earnings increased $7.4 million, or 15%, to $57.9 million, or $1.95 per diluted share, compared to $50.5 million, or $1.70 per diluted share for 2013. Return on average assets increased 10 basis points to 1.22% compared to 1.12% for 2013 and return on average equity increased 50 basis points to 9.71% compared to 9.21% for 2013. The improvement in earnings was primarily due to an increase in net interest income of $8.8 million, or 6.4%, and a decrease in the provision for loan losses of $6.6 million, or 79%. The increase in net interest income was primarily due to strong average loan growth of $259 million during 2014. Net interest margin was stable at 3.50% for both 2014 and 2013. The provision for loan losses decreased due to a significant improvement in asset quality with only $58 thousand in net charge-offs in 2014. Despite significant growth in 2014, expenses remained well controlled with a decrease of $0.2 million.

Asset quality improved significantly throughout 2014. Total nonperforming loans were $12.5 million, or 0.32% of total loans, at December 31, 2014, which represents a 45% decrease from $22.5 million, or 0.63% of total loans, at December 31, 2013. Special mention and substandard loans also decreased $49.1 million, or 26%, to $138.6 million from $187.7 million at December 31, 2013.

S&T’s growth strategy continued in 2014 with expansion through a new loan production office in Central Ohio and a new branch and lending team in State College, Pennsylvania.

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S&T Earnings Release –4

S&T Bancorp, Inc. Announces Fourth Quarter and Full Year 2014

Results and Declares Fourth Quarter Dividend

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The merger with Integrity Bancshares, Inc. was announced on October 30, 2014 and is expected to close in the first quarter of 2015. Integrity has eight branches in south-central Pennsylvania and assets of $844 million as of December 31, 2014.

Financial Condition

Total assets increased $57.9 million to $5.0 billion at December 31, 2014 compared to $4.9 billion at September 30, 2014 and increased $432 million compared to $4.5 billion at December 31, 2013. Portfolio loan growth was strong during the quarter with an increase of $67.6 million, or a 7.1% annualized rate. Commercial loans grew $71.0 million during the quarter, or a 10% annualized rate, due to growth in the commercial and industrial and construction portfolios. Total deposits were unchanged at $3.9 billion for the quarter. S&T’s risk-based capital ratios were little changed this quarter with retained earnings growth keeping pace with loan growth. All capital ratios remain significantly above the well-capitalized thresholds of federal bank regulatory agencies.

Dividend

The Board of Directors of S&T declared a $0.18 per share cash dividend at its regular meeting held January 26, 2015. This is an increase of 12.5% compared to a common stock dividend of $0.16 per share declared in the fourth quarter of 2013. The dividend is payable February 26, 2015 to shareholders of record on February 12, 2015. Dividends declared in 2014 increased $0.07, or 11.5%, to $0.68 compared to $0.61 for 2013.

Conference Call

S&T will host its fourth quarter 2014 earnings conference call live over the Internet at 1:00 p.m. ET on Tuesday, January 27, 2015. To access the webcast, go to S&T’s webpage at www.stbancorp.com and click on “Events & Presentations.” Select “4th Quarter 2014 Conference Call” and follow the instructions.

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S&T Earnings Release –5

S&T Bancorp, Inc. Announces Fourth Quarter and Full Year 2014

Results and Declares Fourth Quarter Dividend

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About S&T Bancorp, Inc.

Headquartered in Indiana, Pennsylvania, S&T Bank operates offices within Allegheny, Armstrong, Blair, Butler, Cambria, Centre, Clarion, Clearfield, Indiana, Jefferson, Washington and Westmoreland counties, as well as loan production offices in northeast and central Ohio. With assets of $5.0 billion, S&T stock trades on the NASDAQ Global Select Market System under the symbol STBA. For more information, visit www.stbancorp.com.

This information may contain forward-looking statements regarding future financial performance which are not historical facts and which involve risks and uncertainties. Actual results and performance could differ materially from those anticipated by these forward-looking statements. Factors that could cause such a difference include, but are not limited to, general economic conditions, change in interest rates, deposit flows, loan demand, and asset quality, including real estate and other collateral values and competition. In addition to the results of operations presented in accordance with Generally Accepted Accounting Principles (GAAP), S&T management uses and this press release contains or references, certain non-GAAP financial measures, such as net interest income on a fully taxable equivalent basis. S&T believes these non-GAAP financial measures provide information useful to investors in understanding our underlying operational performance and our business and performance trends as they facilitate comparisons with the performance of others in the financial services industry. Although S&T believes that these non-GAAP financial measures enhance investors’ understanding of S&T’s business and performance, these non-GAAP financial measures should not be considered an alternative to GAAP. A reconciliation of these non-GAAP financial measures is presented in the attached selected financial data spreadsheet. This information should be read in conjunction with the audited financial statements and analysis as presented in the Annual Report on Form 10-K for S&T Bancorp, Inc. and subsidiaries.

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Definitions and Reconciliation of GAAP to Non-GAAP Financial Measures:

Definitions and Reconciliation of GAAP to Non-GAAP Financial Measures: