Greenwood is known for his patriotic signature song "God Bless the U.S.A.", which was originally released and successful in 1984, and became popular again during the Gulf War in 1991 and after the September 11, 2001, attacks (becoming his highest charting pop hit, reaching number 16 on the "Billboard" Hot 100), and again during the 2016 and 2020 American Presidential Elections as President Donald Trump's rally introduction track. He also has charted seven number-ones on the US Hot Country Songs list in his career: "Somebody's Gonna Love You", "Going, Going, Gone", "Dixie Road", "I Don't Mind the Thorns (If You're the Rose)", "Don't Underestimate My Love For You", "Hearts Aren't Made to Break (They're Made to Love)", and "Mornin' Ride". His 1983 single "I.O.U." was also a top-five hit on the adult contemporary charts, and a number 53 on the Hot 100.