Brendan Marston joined Manitowoc, Wis.-based Bank First as chief operations officer. .Marston has more than 20 years of operational leadership experience, most recently as senior vice president and director of bank operations at Green Bay, Wis.-based Associated Bank. Marston has a master’s degree in organizational leadership. “Brendan’s proven leadership and deep expertise in banking operations will be instrumental as we advance strategic initiatives aimed at delivering a remarkable experience for our customers,” said Bank First President Tim McFarlane, president of the $4.5 billion bank. “His focus on operational excellence will also support our employees in providing the highest level of service.”