According to the "Oracle of Bacon," Lee ranks 24th on the list of the most connected actors in Hollywood. This rating is determined by calculating the number of people who appeared directly with Lee, within one degree of Lee, etc. Per IMDB, he appeared with 4998 different actors in his career.
To put that in perspective, Kevin Bacon is #411 on the list, and he's appeared with 3045 people.
#1 on the list is Eric Roberts, who's appeared with 8474 different actors in his career. Samuel L. Jackson at #5 has "only" appeared with 6088 different actors, and Michael Caine at #10 with 5164. Danny Trejo really gets around. He's appeared with 6906 different actors in his career.
The top actress on the list is Sally Kirkland at #47.
A big factor in the totals of actors like Trejo, Roberts, and Michael Madsen are the large number of quick, cheap, direct to video movies in which they've appeared. Older actors don't fare that well, in large part because the IMDB records are sketchy the further back they go. It's generally accepted that actors like John Carradine and Donald Crisp had huge totals but the records simply aren't there. Carradine in particular appeared in a number of schlocky foreign horror films late in his career for which he would fly in for a day and film a handful of (usually mad scientist) scenes that would get cut into numerous movies, so Carradine himself probably never knew how many films he was actually in.
The top 20:
Eric Roberts (I) (2.83285)
2. Michael Madsen (I) (2.85125)
3. Harvey Keitel (2.85789)
4. Danny Trejo (2.85820)
5. Samuel L. Jackson (2.86360)
6. Robert De Niro (2.86777)
7. Donald Sutherland (I) (2.86991)
8. Udo Kier (2.87229)
9. Malcolm McDowell (2.87378)
10. Michael Caine (I) (2.87567)
11. Martin Sheen (2.87602)
12. Willem Dafoe (2.87956)
13. Seymour Cassel (2.88339)
14. Morgan Freeman (I) (2.88826)
15. David Carradine (2.88939)
16. John Hurt (2.89290)
17. Dennis Hopper (2.89446)
18. Christopher Plummer (I) (2.89467)
19. John Savage (I) (2.89628)
20. Max von Sydow (I) (2.89663)
