- Parents worked in the field of commercial jingles: His father was a composer and his mother was a singer.
- Sang backup on the Lionel Richie hits "All Night Long" and "Running With the Night."
- Met his wife Cynthia Rhodes while writing a song for her film Staying Alive (1983); has also contributed music to the sound tracks for St. Elmo's Fire (1985), The Goonies (1985) and Tequila Sunrise (1988).
- To promote his 1991 album, Rush Street, he performed five concerts in a 24-hour period, starting in Baltimore and finishing in Los Angeles.
- Wrote and produced the 2000 'N Sync hit "This I Promise You."
- Wrote Keith Urban's 2011 country hit "Long Hot Summer," which gave Marx a run of four consecutive decades in which tunes Marx wrote or cowrote were chart-toppers.
- Was music producer for short-lived series The Playboy Club.
- Sang "The Star -Spangled Banner" at the 2011 Auto Club 400.
- 2003, Grammy — Song of the Year: Winner
- Brandon Marx — Son
- Dick Marx — Father
- Cynthia Rhodes — Ex-wife
- Ruth Marx — Mother
- Jesse Marx — Son
- Lucas Marx — Son
- Daisy Fuentes — Wife