Headquartered in Princeton, N.J., Withum provides a long list of services, including accounting, auditing, employee benefit services, pension plans services, tax services, litigation support, business valuation, insolvency services, transaction advisory services, and management consulting. The firm has also expanded to include digital and technology transformation services, cyber and information security services, and outsourced accounting systems and services for clients.

The firm takes its name from Frederick Withum, Leonard Smith, and Ivan Brown, who founded their self-titled company in 1974 in Middlesex County, N.J. The firm’s founders began their careers at larger accounting firms, and when they struck out on their own, their idea was to provide personalized service to companies that were still growing. They also decided that they wanted their firm to be "people-focused," putting the emphasis on both client service and staff development.