Charles J. Zwick, who as President Lyndon B. Johnson’s last budget director helped engineer the only federal surplus posted within a span of nearly four decades, died Friday at his home in Coral Gables, Fla. He was 91. Dr. Zwick was director of the Bureau of the Budget (now the White House Office of Management and Budget) for a year, until Johnson left office in January 1969. He was then chief executive of Southeast Banking Corp. in Florida until 1991, when he resigned after the firm recorded losses in real estate. In 2010, Dr. Zwick gave $1 million to the University of Connecticut to finance the expansion of the renamed Charles J. Zwick Center for Food and Resource Policy, which seeks market solutions to problems involving food and energy. In 2011, he donated $1 million to the RAND Corp. to establish the Zwick Impact Fund, which has studied autonomous vehicle safety, the benefits of educating prison inmates, and the cost of caring for patients with dementia. Charles John Zwick was born on July 17, 1926, in Southington, Connecticut.He went to the University of Connecticut, where the only A grade he received as a freshman was in economics. He enlisted in the Army and served in Japan after World War II, then completed his bachelor’s and master’s degrees in agricultural economics in 1950 and 1951 at the University of Connecticut. He earned a doctorate in economics from Harvard. Dr. Zwick was a researcher at the RAND Corp. from 1956 to 1965, heading its logistics department and studying urban transportation and Air Force efficiency.