The Helena National Bank was opened for general banking business on September 1, 1890, in the Power Block at 58 N. Main Street, Helena, Montana. At the time of the opening, the new bank possessed capital of $500,000, "equal to that of any other Helena bank." Officers in the early years of Helena National Bank included John T. Murphy, president, (of the Murphy, Neel and Company mercantile firm); Shirley C. Ashby, vice president and later president (the head of one of Montana's leading agriculture houses); and Frank Baird, cashier from 1890 to 1894.

During the panic of 1893, Helena National Bank negotiated a consolidation with the city's Second National Bank whose president was Erastus D. Edgerton. The merger was completed on October 1st, the two banking houses joining under the name of Helena National Bank with Edgerton assuming the office of president for the consolidated banks. At the time of the merger, there were suggestions of improprieties in the handling of a loan to D.A.G. Floweree by Helena National's president, Shirley C. Ashby.

Helena National Bank continued to operate through 1894. However, at the end of that year, the stockholders were asked to consider a merger of the bank with the reorganized First National Bank of Helena. The merger was approved and became effective on January 1, 1895. All Helena National assets were transferred to First National and the liquidation completed. Helena National stockholders were offered the exchange of their stock for that of the First National Bank at eighty per cent of the value of the Helena National certificates (Helena National stock having been reduced by the Comptroller), or they could retain their stock and receive payment following the collection of Helena National Bank assets. Most stockholders agreed to the stock exchange. E.D. Edgerton remained an officer following the merger, becoming a vice president and manager of First National Bank.