In front of a packed-out Wembley Stadium, England beat Germany and won the European Championship in dramatic fashion.
In front of a record-breaking crowd of 87,192, Kelly's eleventh-minute winner secured England the country's first major international success since 1966.
The captain said this was the proudest day of his life.
After a goalless but entertaining first half, the Lionesses were in front after 60 minutes thanks to a brilliant strike byElla Toone.
Toone's path was created by a superb Keira Walsh pass that set up her team-mate. She spotted the German keeper off her line and went for the ball, chipping the ball past him and sending Wembley into raptures.
Germany was not to be down for long, as they were able to tie the game in the 78th minute. Tabea Wassmuth was the one who scored the goal, after Tabea was found inside the area.
England broke the stalemate with 10 minutes to play in the first period of extra-time. Kelly's shot came back to her feet inside the six-yard box as Germany couldn't clear a corner. She turned around and won the trophy for England.
England started the better of the two teams in front of a record-breaking crowd. Fran Kirby sent in a cross that was met by Ellen White but her head didn't hit the ground.
The Germans had a chance in the 25th minute. Mary Earps pounced on the ball after Georgia Stanway nodded on a Germany corner.
There was a chance that England would take the lead before the break. White was leaning as she hit the ball, which went over the bar.
The Germans should have taken the lead after the break. After poking the ball just wide of the post, she was replaced by Toone, who scored England's second goal just after the hour.
They should have been able to tie it up soon after. Her curling effort couldn't find the post as she tried to test England. Earps was able to scoop up the rebound, but she was not able to stop Magull from tying the game with 11 minutes to go.
Neither side wanted to give anything away during the extra time. There was a chance of a penalty shoot out against the Germans.
Kelly was just 24 years old when she scored the winner to send Wembley into a frenzy.