Who's Appeared The Most?

For the sake of calculating this list, archive footage used in an episode does not count; the actor involved must have filmed new material in any given episode:

1 David Tennant
48 episodes
Playing: The Doctor
"The Parting Of The Ways" to "The End Of Time, Part Two"

2 Billie Piper
33 (34*) episodes
Playing: Rose Tyler
"Rose" to "Doomsday", "Partners In Crime", "The Poison Sky", "Midnight" to "Journey's End", "The End Of Time, Part Two"*
Notes: (*) Appearance in "The End Of Time" currently unconfirmed

3 Paul Kasey
27 episodes
Playing: Auton ("Rose"), Coffa ("The End Of The World"), Slitheen (“Aliens Of London", "World War III"), Zu-Zana ("Bad Wolf"), Clockwork Droid ("The Girl In The Fireplace"), various Cybermen of various ranks ("Rise Of The Cybermen", "The Age Of Steel", "Army Of Ghosts", "Doomsday", "The Next Doctor"), Ood ("The Impossible Planet", "The Satan Pit"), Ood Sigma ("Planet Of The Ood", "The Waters Of Mars", "The End Of Time, Parts One and Two"), the Hoix ("Love & Monsters"), Robot Santas ("The Christmas Invasion", "The Runaway Bride"), Judoon Captain ("Smith And Jones", "The Stolen Earth"), pig slave (aka, Hero Pig – "Daleks In Manhattan", "Evolution Of The Daleks"), Host ("Voyage Of The Damned"), Hath Peck ("The Doctor's Daughter"), Sorvin ("Planet Of The Dead")

4 Freema Agyeman
19 (20*) episodes
Playing: Adeola Oshodi ("Army Of Ghosts"), Martha Jones ("Smith And Jones" to "Last Of The Time Lords", "The Sontaran Stratagem" to "The Doctor's Daughter", "The Stolen Earth", "Journey's End", "The End Of Time, Part Two")
Notes: (*) Appearance in "The End Of Time" currently unconfirmed

5 Catherine Tate
17 episodes
Playing: Donna Noble
"Doomsday" to "Journey' End", "The End Of Time Parts One and Two"

6 Nicholas Briggs
15 episodes
Playing: Voice of the Nestene Consciousness ("Rose"), Dalek voices ("Dalek", "Bad Wolf", The Parting Of The Ways", "Army Of Ghosts", "Doomsday", "Daleks In Manhattan", "Evolution Of The Daleks", "The Stolen Earth", "Journey’s End"), Jagrafess voice ("The Long Game"), Cyberman voices ("The Rise Of The Cybermen", "The Age Of Steel", "Army Of Ghosts", "Doomsday", The Next Doctor"), Judoon voices ("Smith And Jones", "The Stolen Earth")

7 Camille Coduri
14 (15*) episodes
Playing: Jackie Tyler
"Rose", "The End Of The World", "Aliens Of London", "World War III", "Father's Day", "The Parting Of The Ways" to "New Earth", "Rise Of The Cybermen", "The Age Of Steel", "Love & Monsters", "Army Of Ghosts", "Doomsday", "Journey's End", "The End Of Time, Part Two"*
Notes: (*) Appearance in "The End Of Time" currently unconfirmed

8 Noel Clarke
14 episodes
Playing: Mickey Smith
"Rose", "Aliens Of London", "Aliens Of London", "Boom Town", "The Parting Of The Ways" to "New Earth", "School Reunion" to "The Age Of Steel", "Army Of Ghosts", "Doomsday", "Journey's End".
Notes: Mickey also appeared in "Father's Day", but only as a young child, not played by Noel Clarke.

9 Christopher Eccleston
13 episodes
Playing: The Doctor
"Rose" to "The Parting Of The Ways"

10 John Barrowman
10 (11*) episodes
Playing: Captain Jack Harkness
"The Empty Child" to "The Parting Of The Ways", "Utopia" to "Last Of The Time Lords", "The Stolen Earth", "Journey's End", "The End Of Time, Part Two"*
Notes: (*) Appearance in "The End Of Time" currently unconfirmed

=11 Jacqueline King
9 episodes
Playing: Sylvia Noble
"The Runaway Bride", "Partners In Crime", "The Sontaran Stratagem", "The Poison Sky", "Turn Left", "The Stolen Earth", "Journey's End", "The End Of Time, Parts One and Two"

=11 Bernard Cribbins
9 episodes
Playing: Wilfred Mott
"Voyage Of The Damned", "Partners In Crime", "The Sontaran Stratagem", "The Poison Sky", "Turn Left", "The Stolen Earth", "Journey's End", "The End Of Time, Parts One and Two"

=11 Barnaby Edwards
9 epsiodes
Playing: Dalek operator ("Dalek", "Bad Wolf", "The Parting Of The Ways", "Army Of Ghosts", "Doomsday", "Daleks In Manhattan", "Evolution Of The Daleks", "The Stolen Earth", "Journey's End")

=14 Lachele Carl
8 episodes
Playing: Newsreader Trinity Wells
"Aliens Of London", "World War III", "The Christmas Invasion" , "The Sound Of Drums", "The Poison Sky", "Turn Left", "The Stolen Earth", "The End Of Time, Part One"
Note: There' s no evidence yet she's in "The End Of Time, Part Two", but there is the slight chance she could be.
Note (2): Trinity is so far the only character to have appeared in the Wholy Trinity of Doctor Who, Torchwood and The Sarah Jane Adventures.

=14 Alan Ruscoe
8 episodes
Playing: Lead Auton ("Rose"), Lute ("The End Of The World"), Blon Fel-Fotch Passameer-Day Slitheen ("Aliens Of London", "World War III"), Trin-E ("Bad Wolf"), Anne Droid ("Bad Wolf", "The Parting Of The Ways"), Andy Stone ("The Waters Of Mars")

=14 Adjoa Andoh
8 episodes
Playing: Sister Jatt ("New Earth"), Francine Jones ("Smith And Jones", "The Lazarus Experiment", "42", "The Sound Of Drums", "The Last Of The Timelords", "The Stolen Earth", "Journey's End").

=14 Nicholas Pegg
8 episodes
Playing Dalek operator in "Bad Wolf", "The Parting Of The Ways", "Army Of Ghosts", "Doomsday", "Daleks In Manhattan", "Evolution Of The Daleks", "The Stolen Earth", "Journey's End"

=14 David Hankinson
8 episodes
Playing Dalek operator in "Bad Wolf", "The Parting Of The Ways", "Army Of Ghosts", "Doomsday", "Daleks In Manhattan", "Evolution Of The Daleks", "The Stolen Earth", "Journey's End"

19 John Simm
5 episodes
Playing: The Master
"Utopia" to "Last Of The Time Lords", "The End Of Time, Parts One and Two"