Winder continued to prosper during most of the first half of the 20th Century. Industries undertook the manufacture of overalls, hardware, textiles and the processing of cotton. Additional banks opened and, in 1907, the Winder News began publishing. After World War I, during which Winder contributed many young men, major public investments were made, including the paving of Broad Street, creation of an electric light system and construction of a waterworks. Highway 29 was paved from Lawrenceville to Winder in 1930, and, during the following year, a nearby local resident, Richard B. Russell, Jr., was inaugurated as governor of Georgia. Later, upon his election to the U.S. Senate, Russell obtained an appropriation, in 1943, to construct a local airport, which was opened in 1948.

Many important events helped to modernize Winder after World War II. Major public improvements led this modernization, inluding the Winder-Barrow County Hospital, the groundbreaking ceremony taking place in August of 1950. Construction was begun on the new Federal Building, which opened in 1967, the same year which saw Fort Yargo become a Georgia State Park. During the late 1970s, important investments were made in Downtown, including the restoration of the depot, improvements to downtown sidewalks, and renovation of City Hall and the police and fire stations. Following a fire that destroyed two buildings at Broad and Candler streets, the City created a small park and parking lot on the site. Plans were drawn for a civic center and new police and fire facilities, which were completed in 1986. A new headquarters for the Piedmont Regional Library was dedicated in 1988, and the new Barrow County Courthouse annex was opened in 1990. That year, Winder was a City of 7,373 inhabitants.

All of these accomplishments were celebrated by the citizens of Winder in 1993, with the commemoration of the City's 100th anniversary. A bronze marker was attached to the Winder City Hall by Mayor Buddy Outzs, which read: "To commemorate 100 years as the City of Winder, 1893-1993."