- "What are we?"
"We're a team!"
- ―Michael Peterson and Ace Peterson
Ace Peterson is the son of Michael Peterson and a big fan of the Heroes of New York. He was distraught when he received word that his father had died; however, unbeknownst to everyone, the Centipede Project had faked his father's death. He was imprisoned by HYDRA, but freed by Coulson's Team and was brought back to his aunt, Mindy Peterson.
Ace Peterson lived with his father, Michael, and his mother, until his father suffered a back injury that caused him to lose his job, and his mother abandoned them both. Despite this, Ace remained close to his father, who often acknowledged this relationship by calling themselves a "Team". After the Battle of New York, Ace became a huge fan of the so-called Heroes of New York.
A few months after that event, Ace went with his father to buy one of the action-figures of these Heroes, but when watching the toy shop window, both Ace and Michael realized that their current financial situation would not allow them to afford a birthday present.
In that moment, a nearby building exploded, and Michael, who had been previously enhanced with the Centipede Serum, which granted him strength beyond a normal human, entered the building to rescue some of the occupants. While Michael saved a woman, Ace was taken care of by a nearby hot-dog vendor.
When his father's condition began to deteriorate, both mentally and physically, due to the Extremis that the Centipede Device injected in his blood, Michael thought that the best option was to flee both S.H.I.E.L.D. and the recently exposed Centipede Project and to make Skye erase all files about them and take them to the nearest train station to rebuild their lives in a new place.
Michael kidnapped both Ace and Skye, but was confronted by Agent Phil Coulson and successfully subdued and stabilized. Ace was taken to live with Mike's sister Mindy while his father was then taken into S.H.I.E.L.D. protective custody for rehabilitation.
Kidnapping by the Centipede Group
Michael sent him all the Heroes of New York action-figures, and Ace was happy to know that his father had a job. However, Michael had never visited his son since he arrived to the S.H.I.E.L.D. Training Facility, because he was too embarrassed that the last time Ace saw him, he was a "monster" due to the mental instability caused by the Centipede Serum.
Encouraged by Agent Phil Coulson, Michael decided to call his son to tell him he would return to see him, only to have Raina, who had somehow found Ace's location, threaten to kill him if Peterson did not trade Coulson for Ace. With no choice, Mike was forced to trick Coulson's Team into thinking they wanted him.
When the exchange started, Mike attempted to break off the deal by threatening Raina's life but Coulson told him it was okay, understanding that he had no other choice. After Ace was taken to safety in Skye's care, Michael attempted to redeem himself by going back to rescue Coulson only for Raina and her group to have the area explode, brutally burning him and destroying his right leg.
Son of Deathlok
Michael, now under the thrall of the Clairvoyant, and an unwilling operative of the Centipede Project, asked his handlers through his Backscatter X-Ray Eye Implant for permission to see his son and let him know that he was alive, but he was told "Not yet".
When S.H.I.E.L.D. Agent Felix Blake was attacked by Deathlok at Tranquility Bridge assisted living home, Blake attempted to persuade Mike Peterson to stop by mentioning that Peterson had a son that missed him. Deathlok responded that Mike Peterson was dead before critically injuring Blake.
During the HYDRA Uprising, Ace was seized by HYDRA forces and imprisoned at a Cybertek facility as an incentive for his father to follow orders. After Deathlok captured Skye who was escaping from Grant Ward, Skye reminded Peterson of his son. Peterson reminded her that Ace was left in her protection, but she gave him to what is now a defunct organization. 
John Garrett would use seeing pictures of Ace as Deathlok's reward for doing his work. After Deathlok decapitated a South American drug lord for Ian Quinn's super-soldier scheme, Garrett rewarded him by downloading pictures of Ace's activities. When Raina and Deathlok discussed their motives for working with Garrett, Deathlok explained how his son was Garrett's prisoner.
Ace was freed when Skye released all of the prisoners used to force Cybertek personnel to work for HYDRA. His freedom allowed Deathlok to act against Garrett without fear. He was re-united with his aunt Mindy, but not his father, who felt too ashamed to approach him.
- S.H.I.E.L.D. (First Incarnation) - Protectors
- ↑ 1.0 1.1 Agents of S.H.I.E.L.D.: 1.01: Pilot
- ↑ Agents of S.H.I.E.L.D.: 1.10: The Bridge
- ↑ Agents of S.H.I.E.L.D.: 1.13: T.R.A.C.K.S.
- ↑ Agents of S.H.I.E.L.D.: 1.16: End of the Beginning
- ↑ Agents of S.H.I.E.L.D.: 1.20: Nothing Personal
- ↑ Agents of S.H.I.E.L.D.: 1.21: Ragtag
- ↑ Agents of S.H.I.E.L.D.: 1.22: Beginning of the End