The World Sport Star of the Year is voted on by the British Broadcasting Corporation.
The first two steeplechases were the only ones where a woman had ever finished.
Blackmore was the first woman to be leading jockey at the Cheltenham Festival, where she racked up six victories.
She said that she was very happy to receive the World Sport Star award.
The support has been great. I got a kick out of being on that list. She said this is incredible.
My dreams were so big, but this year was much bigger than I could have imagined.
I feel very privileged to have had a year like this.
The previous best finish by a female rider in the National was by Walsh. Only 19 female jockeys have competed in the race, because women were not allowed to ride in the race until 1977.
Mexican boxer Saul 'Canelo' Alvarez, American football quarterback Tom Brady, Serbia's world number one tennis player Novak Djokovic, Jamaican sprinter Elaine Thompson-Herah, and Dutch Formula 1 world champion Max Verstappen were all in the running to win the online public vote.
The winner of the award in 2020 was a Russian fighter.
