To reach the final, Marx knocked off future International Tennis Hall of Fame member John Doeg in the round of 16, Frank Froehling Jr. in the quarterfinals, and Gardner Larned in the semifinals.

Riggs had blown through his competition to reach the final, and Marx gave him his toughest test of the tournament, stretching the future Hall of Famer to five sets before falling, 11–9, 6–2, 4–6, 6–8, 6–1.

Marx spent four years in the United States Coast Guard during World War II serving in the South Pacific.

Marx was hospitalized at Tacloban for malaria; and, when discharged, was assigned to form and be master of ceremonies of an amateur show providing entertainment for those in rear areas passed over by U.S.O.

[4] After the war he worked as an advertising copywriter, a radio gag man for Milton Berle, and a writer of Hollywood movies (including four for Bob Hope), Broadway plays and TV scripts for such hit shows as My Three Sons, All in the Family, and Alice.

Marx wrote the foreword to Michael R. Crider's 2007 tome, The Guy's Guide to Dating, Getting Hitched and the First Year of Marriage, a humorous look at relationships.