Season 1

Season One consists of 24 episodes that aired in the United States beginning September 22, 2010, and ending May 18, 2011. The first sixteen episodes aired on Wednesdays at 8:00 pm, after which the series moved to Wednesdays 10:00pm.

Principal cast
In order of character appearances
 * Jensen Ackles as James Harrison (24/24)
 * Jared Padalaki as Sam Harrison (24/24)
 * TBA as Danielle Harrison (24/24)
 * Eliza Dushu as Katherine Winters (16/24)
 * Jeffery Dean Morgan as John Harrison (15/24)*
 * Kristen Bell as Laura Price (16/24)**
 * TBA as Michael Hart (8/24)***

*Only listed in the episodes he appeared in through "Homecoming," and then became a full regular.

**Listed as a guest star until "The Cult".

**Listed as a regular until "Coming Home" and then a special guest star in "A Family Ties.

Trivia

 * Katherine does not appear in 8 episodes:
 * #3 Hook Man, #5 Bloody Mary , #7 House of the Rising Kelly, #14 The Cult , #15 Homecoming , #16 Outlaws #17 TBA and #18 The Demon Who Came In From The Cold.
 * John does not appear in episodes 10:
 * #3 Hook Man, # 4 Dead Man Walking , #5 Bloody Mary , #7 House of the Rising Kelly , # 8 Shape Shifter , #10 The Wendigo , #12 Mutant X , #14 The Cult , #17 TBA and #19 Darla.
 * Laura does not appear in 8 episodes:
 * #3 Hook Man, #5 Bloody Mary , #6 The Halloween Party, #10 The Wendigo , #11 Bloodlines , #15 Homecoming , #18 The Demon Who Came In From The Cold and #19 Darla.


 * Michael does not appear in 2 episodes during his time as a regular:
 * #3 Hook Man and #7 House of the Rising Kelly.
 * James, Danielle and Sam learn Laura knows the secret about the supernatural world in episode 13 "A Family Ties" and that John and Laura worked together during episdoe 20 "Dead Man's Blood".
 * Katherine learns the Harrison's are hunters in episode 19 "Darla".
 * The writers revealed the reason Eliza Dushu's character Katherine did not appear in all episodes during season 1, was due to her character being unknown to the supernatural world, but revealed that her uncovering the truth at the end of season 1, will mean more screentime and bigger roles in season 2.