Jenna Harrison

James and Katherine's Wedding
At the wedding, Jenna appears and reunites with her brothers. She is corporal and back for 48 hours just enough time to see the wedding and reception. She gets her first taste of a demon vanquish, and throws a potion. However before the wedding occurs a second time, her reveals that still it isn't for her. (6x17 The Wedding From Hell)

Helping with gypsies
When the brothers learn that their deceased sister Jenna had come in contact with gypsies, they contact her spirit to help them. She directs them to an old friend. Later, Johnny contacts Jenna again and asks for some advise on how to deal with his girlfriend. (7x6 The Eyes Have It )

The Final Battle
Jacob goes into the past trying to find the special dagger that will help them in their victory, and to try and save the lives of his brothers. He time travels to the past, and meets his parents, past Debra and his sister Jenna. Learning that Jenna knows where the dagger is, he asks her help. Not wanting any part with the magical world, she refuses at first. When Jacob reveals that his brothers are all dead, she assists him. They locate the dagger, without wanting to know the future. Jacob gives her a potion that will wipe her memory of this visit.

Appearances
Total episode count: 15

Season 1 Season 2 Season 3 Season 4 Season 5 Season 6 Season 7 Season 9
 * Something Warlock This Way Comes - 1x1
 * Destiny's Calling - 1x2 (flashback) 
 * A Family Ties - 1x12 (flashback) 
 * The Demon Who Came In From The Cold - 1x18 (flashback as a 12 year old girl) 
 * Exit Strategy - 1x22 (flashback) 
 * Night Terrors in New Orleans - 2x17 (as part of a dream) 
 * The Old Normal - 2x22  (alternate universe)
 * A Very Warlock Christmas - 3x9 (flashback) 
 * The Walking Dead - 4x22 (as a zombie) 
 * Free to Be Me or You - 5x3 (manifestation) 
 * The Wedding From Hell - 6x17
 * The Eyes Have It - 7x6 (as a spirit) 
 * Magical History Lesson - 9x12 (flashback) 
 * "Till Charmed Do Us Part (Part 1)" - 9x23 (flashback) 
 * "Till Charmed Do Us Part (Part 2)" - 9x24 (In the past) 

Trivia

 * Jenna Harrison is the only sibling who did not inherit any powers.
 * Jenna Harrison has appeared in every season except season 8.
 * Jenna is the first character to be killed on the series in present day.
 * Jenna has appeared in 15 episodes throughout the series, but only 3 of them are during present day in "Something Warlock This Way Comes" where she dies, "The Wedding From Hell" 48 hour visit for James wedding and The Eyes Have it as a spirit.
 * Being the oldest of the five Harrison siblings, she and James are only 5 years apart in age difference.
 * Both the original script draft and the shooting script give more insight into Jenna Harrison's background and job.
 * In the original script draft Jenna Harrison's character lived, and would serve the same role as Deborah. In this version however Its their uncle who passes away and raised them.
 * Both the first-draft script and the shooting script include a scene in which Jenna Harrison contacts Joshua and asks him to come visit her, the scene was cut and instead it goes directly to Jenna's death after the flashback in the past.
 * At Comic Con 2015, The producers mentioned that the character of Jenna was originally suppose to be alot more major, and got replaced by Debra. The decision was because they felt that killing off an older sibling proved more motivating, and that her background not wanting to know magic and voodoo was better. But looking back, her character proved to be popular and the planned to never have her show up in the present outside of flashbacks, dreams or alternate worlds. Her appearance at James wedding marked the first time we see the real Jenna since her death, but revealed it was only a one time thing and didn't want to overdo it.