Robert Downey Jr. has acted in many, many films over his career. His career started in 1970's Pound under the name Bob Downey, as Puppy. This was followed by an uncredited appearance in 1972's Greaser's Palace. His other credits include:

1. Moment to Moment (1975)-uncredited
2. Mad Magazine Presents Up the Acadamy (1980)-uncredited
3. Baby It's You (1983) as Stewart
4. Firstborn (1984) as Lee
5. Deadwait (1985)
6. Tuff Turf (1985) as Jimmy Parker (under the name Robert Downey)
7. Weird Science (1985) as Ian (one of the jerky popular guys)
8. Mussolini: The Untold Story (1985)- TV mini-series; as Bruno Mussolini
9. Back to School (1986) as Derek
10. America (1986) as Paulie Hackley
11. The Pick-Up Artist (1987) as Jack Jericho
12. Less Than Zero (1987) as Julian Wells
13. Johnny Be Good (1988) as Leo Wiggins
14. Rented Lips (1988) as Wolf Dangler
15. 1969 (1988) as Ralph Carr
16. That's Adequate (1989) as Albert Einstein
17. True Believer (1989) as Roger Baron
18. Chances Are (1989) as Alex Finch
19. Air America (1990) as Billy Covington
20. Too Much Sun (1991) as Reed Richmond
21. Soapdish (1991) as David Seton Barnes
22. Chaplin (1992) as Charles Spencer Chaplin
23. Luck, Trust & Ketchup: Robert Altman in Carver County (1993) as himself
24. Heart and Souls (1993) as Thomas Reilly
25. The Last Party (1993) as himself (also writer on project)
26. Short Cuts (1993) as Bill Bush
27. Hail Caesar (1994) as Jerry
28. A Century of Cinema (1994) as himself
29. Natural Born Killers (1994) as Wayne Gale
30. Only You (1994) as Peter
31. Richard III (1995) as Lord Rivers
32. Home for the Holidays (1995) as Tommy Larson
33. Mr. Willowby's Christmas Tree (1995) TV movie; as Mr. Willowby
34. Restoration (1995) as Robert Merivel
35. Danger Zone (1997) as Jim Scott
36. One Night Stand (1997) as Charlie
37. Two Girls and a Guy (1997) as Blake Allen (also did writing and performing for soundtrack)
38. Hugo Pool (1997) as Fraz Mazur
39. The Gingerbread Man (1998) as Clyde Pell
40. U.S. Marshals (1998) as Special Agent John Royce
41. In Dreams (1999) as Vivian Thompson
42. Friends & Lovers (1999) as Hans (also did writing and performing for soundtrack)
43. Bowfinger (1999) as Jerry Renfro
44. Black and White (1999) as Terry Donager
45. Wonder Boys (2000) as Tery Crabtree
46. Auto Motives (2000) as Rob
47. Last Party 2000 (2001) as himself
48. Lethargy (2002) as Animal Therapist
49. Whatever We Do (2003) as Bobby
50. The Singing Detective (2003) as Dan Dark (also did work on soundtrack)
51. Charlie: The Life and Art of Charles Chaplin (2003) as himself
52. Gothika (2003) as Pete Graham
53. Eros (2004) as Nick Penrose (segment "Equilibrium)
54. Game 6 (2005) as Steven Schwimmer
55. The Outsider (2005) as himself
56. Kiss Kiss Bang Bang (2005) as Harry Lockhart (also did work on soundtrack)
57. Good Night, and Good Luck (2005) as Joe Wershba
58. Hubert Selby Jr: It'll Be Better Tomorrow (2005) as Narrator
59. The Shaggy Dog (2006) as Dr. Kozak
60. A Scanner Darkly (2006) as James Barris
61. Fur: An Imaginary Portrait of Diane Arbus (2006) as Lionel Sweeney
62. A Guide to Recognizing Your Saints (2006) as Dito (also co-producer)
63. Zodiac (2007) as Paul Avery
64. Lucky You (2007) as Telephone Jack
65. Charlie Bartlett (2007) as Principal Nathan Gardner
66. Iron Man (2008) as Tony Stark/Iron Man
67. The Incredible Hulk (2008) as Tony Stark
68. Tropic Thunder (2008) as Kirk Lazarus
69. The Soloist (2009) as Steve Lopez
70. Sherlock Holmes (set to come out in 2010) as Sherlock Holmes
71. Master Mind (rumored to provide voice work, set to come out in 2010)