Mark Jansen

 was a HouseGuest on Big Brother 19 (US).

He formed a showmance with Elena Davies in week 1, and constantly sided with the group who had power. He was also a victim of Josh Martinez torturing him by banging pots and pans in his face. The former two combined with his and Elena's friendships with Jessica Graf and Cody Nickson eventually made him a target, although Ramses was evicted first. After Jessica was evicted in week 6, and Cody was evicted during the fist half of the first Double Eviction, Mark became the target, but saved him self during the second half of the first double eviction by winning the PoV though Elena was evicted leaving Mark as the sole outsider. When Mark failed to win the PoV in week 8, he was made the replacement nominee and evicted in a 4-2 vote. He came in 9th place, and was the third member of the jury.

Trivia

 * Mark is the first HouseGuest to win immunity through the Temptation Competition.
 * He is also the only HouseGuest to win twice. Ironically he was nominated the week after his safety was up both times, however he also won the Veto and saved himself both times.
 * He is also the only HouseGuest to take an apple from the Tree of Temptation.
 * Mark is the second HouseGuest to win the PoV twice in Big Brother 19, following Paul.
 * Mark is tied with fellow HouseGuest Josh Martinez, Big Brother 11 HouseGuest Michele Noonan, Big Brother 15 HouseGuests Helen Kim and Elissa Slater, and Big Brother 18 HouseGuest Corey Brooks for the most weeks spent as a Have-Not in a single season with four.
 * However, his 4th time being a Have-Not was cancelled due to winning the Have-Not Escape, so his 5th time counts as his 4th week.