The hotel was designed by renowned Palm Beach architect William Manly King, and was considered the social center of Sebring.

From the start, Harder Hall was heralded as "a high class hotel that has been called the finest in Florida" where "the highest types of society gather for balls and social events of the exclusive set".

[14] Featured hotel activities included golfing, tennis, boating, swimming, fishing, hunting, horseback riding, and more.

[18] Beach's brother in law, famed comedian Fred Stone, made national headlines when he went golfing at the resort in 1929, his first public outing without crutches since he had been injured in a plane crash the year before.

Harder Hall "virtually always has been Sebring race headquarters, if not officially, unofficially, and surely socially"[24] Famous guests included actor Steve McQueen, Peter Revson, Dan Gurney[25] Mario Andretti,[26] Count Alfonso de Portago, Briggs Cunningham, Paul Newman, Jim Garner, Dick Smothers, and Bruce Jenner.

[28] In the 30s, Walter Hagen faced off against Joe Kirkwood in an exhibition match at the resort, with Rube Walberg and novelist Rex Beach pairing off for their own round.