Despite his advancing years, he is persuaded to return to the ring by a private mixed martial arts club owner and fight against rivals younger and stronger than him to raise enough money to open a blood bank - a move that will remedy a past mistake and hopefully win back his love.
Khan, one of the most famous faces in India, who shot to fame in the 1989 romantic family drama, Maine Pyar Kiya, told the China Daily in an email interview that he is open to "all genres of film" and decided to shoot Sultan because the story "is very special to me".
"It is about an underdog, fighting against all odds to rise above his failures and to win his lady love back, this was the most appealing thing for me and why I wanted to be a part of the film."
The movie debuted in India in July 2016 and became the country's highest-grossing film that year. When asked about the box office triumph, Khan, who is listed by Forbes magazine as the ninth highest-paid actor in the world, believes the film's focus on family values and love "resonates with the Indian audience".
Despite Khan portraying a number of different roles, Sultan is his first time playing a wrestler. During filming, when the star was 50 years old, Khan embarked on a rigorous training schedule to build up his muscles and master the wrestling skills required for the role.
"I worked with professional wrestlers and also sparred with them. As part of prep, I had to learn wrestling moves and pulls. I had to get my diction right for the character and pick up on body language too," he explained.
