1: 1. Mark Harmon 2. Expanded role as producer 3. Helped create spin-offs

2: 4. Michael Weatherly 5. Directed several episodes 6. Produced "NCIS: New Orleans"

3: 7. Pauley Perrette 8. Wrote and sang theme song 9. Involved in charity work

4: 10. David McCallum 11. Extended cameo in "NCIS: New Orleans" 12. Active in promoting the show

5: 13. Sean Murray 14. Directed episodes 15. Involved in social media campaigns

6: 16. Wilmer Valderrama 17. Produced "NCIS: Los Angeles" 18. Directed and acted in episodes

7: 19. Cote de Pablo 20. Produced "NCIS: New Orleans" 21. Involved in casting decisions

8: 22. Emily Wickersham 23. Directed episode 24. Promoted show on social media

9: 25. Brian Dietzen 26. Directed episodes 27. Involved in marketing strategies