Hopper served in the Chemical Corps during the Vietnam War, where he worked with Agent Orange, an experience he believes to have led to his daughter Sara’s fatal illness.

[4] They divorced after his young daughter died of cancer, which caused him to lapse into alcohol and drug addiction to numb his grief.

Hopper realizes as the season continues that there is a vast conspiracy hiding at Hawkins Lab and he is instrumental in the mission to find and save Will.

[8] In flashbacks, Eleven manages to escape from the Upside Down but is forced to remain hidden in Hopper's cabin in the woods to avoid government agents.

He is once more instrumental in solving the mystery of the demo-dogs and the pumpkin rot, and ultimately takes Eleven to the basement in Hawkins to close the gate once more.

He tries to prepare a written "heart-to-heart" speech, but when he tries to give it, it backfires and Hopper resorts to verbally threatening Mike to stay away from Eleven or he will end their relationship.

Hopper bests them, and he, Joyce, and Murray race for the mall, where they reunite with the children, and learn that the giant Mind Flayer is about to attack but can be stopped if they close the gate to the Upside Down.

Hopper, Joyce, and Murray offer to descend to the base and find the keys Alexei told them about to not only close the gate but destroy the equipment, which would disintegrate anyone left in the room.

[10] Hopper is revealed to have survived the explosion beneath Starcourt Mall, only to be captured by the Russians and sent to a prison camp in Kamchatka.

During his captivity, Hopper bribes and, later, befriends a guard, Dmitri Antonov, through whom he sends Joyce a note indicating he is alive.

Antonov instructs Joyce and Murray to pay $40,000 USD to smuggler Yuri Ismaylov in Alaska in exchange for passage to the Soviet Union.

Hopper manages to briefly escape the prison camp, but Yuri is revealed to have betrayed him and Antonov to the Russians for a larger profit, resulting in his recapture.

Recalling that the creature's weakness is fire, Hopper pockets a lighter and some vodka from a guard, and uses it to create a flaming spear with which he holds back the Demogorgon as it slaughters most of the other prisoners.

Hopper, Joyce and Murray kill the other creatures in the prison to weaken the Upside Down's "hive mind" and give the kids an advantage, while Antonov convinces Yuri to fly them home.

[16] For his performance as Hopper, Harbour was nominated for Outstanding Supporting Actor in a Drama Series at the 69th and 70th Primetime Emmy Awards.