Peacock was born in Cambridge, and grew up in the village of Shepreth.
At age 5, he contracted meningitis, resulting in the disease killing the tissues in his right leg, which was then amputated just below the knee.
Wanting to play football, he was directed to a Paralympic sports talent day when he asked about disability sport in the hospital that fitted his prosthetic leg.
His mother would carry him to school when his very short stump was too sore to wear his prosthetic leg.
Peacock refers to his stump as his "sausage leg."

Peacock ran his first international race at the Paralympic World Cup in Manchester in May 2012.
In June 2012 Peacock set a new 100 metres world record in amputee sprinting at the United States Paralympic track and field trials, recording a time of 10.85 seconds to beat the previous record held by Marlon Shirley by 0.06 seconds.
This record was beaten in July 2013 at the 2013 IPC Athletics World Championships at the Stade du Rhône in Lyon when American athlete Richard Browne recorded a time of 10.83 in the T44 100m semi-finals.

At the 2012 Summer Paralympics, Peacock won the 100m T44 final with a time of 10.90 seconds, claiming the gold and the Paralympic record in the process.
The win made his coach, Dan Pfaff, the only man to have coached 100m gold medalists in both the Olympics and the Paralympics; Pfaff coached Canada's Donovan Bailey, the gold medalist in the 1996 Summer Olympics in Atlanta.

Peacock pulled out of the 2015 IPC Athletics World Championships due to a sore on his stump that developed over the summer.

At the 2016 Summer Paralympics, Peacock defended his title, winning gold in the T44 100m, in 10.81 seconds.

From September 2017 Peacock was a contestant on series 15 of the BBC One programme Strictly Come Dancing, becoming the first amputee paralympian to compete on the show.
Partnered with Oti Mabuse, they were the eighth couple to be eliminated, at the show in Blackpool.
Peacock was born in Cambridge, and grew up in the village of Shepreth. At age 5, he contracted meningitis, resulting in the disease killing the tissues in his right leg, which was then amputated just below the knee. Wanting to play football, he was directed to a Paralympic sports talent day when he asked about disability sport in the hospital that fitted his prosthetic leg. His mother would carry him to school when his very short stump was too sore to wear his prosthetic leg. Peacock refers to his stump as his "sausage leg."
Peacock ran his first international race at the Paralympic World Cup in Manchester in May 2012. In June 2012 Peacock set a new 100 metres world record in amputee sprinting at the United States Paralympic track and field trials, recording a time of 10.85 seconds to beat the previous record held by Marlon Shirley by 0.06 seconds. This record was beaten in July 2013 at the 2013 IPC Athletics World Championships at the Stade du Rhône in Lyon when American athlete Richard Browne recorded a time of 10.83 in the T44 100m semi-finals.
At the 2012 Summer Paralympics, Peacock won the 100m T44 final with a time of 10.90 seconds, claiming the gold and the Paralympic record in the process. The win made his coach, Dan Pfaff, the only man to have coached 100m gold medalists in both the Olympics and the Paralympics; Pfaff coached Canada's Donovan Bailey, the gold medalist in the 1996 Summer Olympics in Atlanta.
Peacock pulled out of the 2015 IPC Athletics World Championships due to a sore on his stump that developed over the summer.
At the 2016 Summer Paralympics, Peacock defended his title, winning gold in the T44 100m, in 10.81 seconds.
From September 2017 Peacock was a contestant on series 15 of the BBC One programme Strictly Come Dancing, becoming the first amputee paralympian to compete on the show. Partnered with Oti Mabuse, they were the eighth couple to be eliminated, at the show in Blackpool.
Jonnie Peacock