Chakradhar is also a name of Lord Vishnu. He is named so because the wheel named Sudarshan keeps rotating in his finger. It is said about this cycle that it is infallible and returns only after destroying the one on whom it is attacked.
When Lord Vishnu incarnated in the form of Shri Krishna in Dwapar, he also had this chakra. He defeated Jarasandh with this chakra, Shishupala was also killed with this chakra. This Chakra was received by Lord Shri Krishna from Parshuram ji in Shri Krishna Avatar, because Lord Rama had handed over the Chakra to Parshuram ji in Ram Avatar and asked to return it in Krishna Avatar.
There is a very interesting story of how and from where Lord Vishnu got this wheel.
It is told in the Vamana Purana that there was a demon named Sridama. It defeated all the gods. After this, a plan was made to snatch Lord Vishnu’s Srivatsa. This enraged Lord Vishnu and started doing penance to Lord Shiva to punish Sridama.
Pleased with the penance of Lord Vishnu, Lord Shiva gave a disc to Lord Vishnu, which was named Sudarshan Chakra. Lord Shiva said that it is unfailing, its attack never goes empty. Lord Vishnu said – Lord, it is unfailing, to test it, I want to attack you first. Lord Shiva said if you want this then try hitting it. Lord Shiva was divided into three parts by the attack of Sudarshan Chakra. After this, Lord Vishnu started repenting for his actions and started worshiping Shiva.
Lord Shiva appeared and said that due to the attack of Sudarshan Chakra, my natural disorder has been cut. I and my nature are not damaged, it is good and indestructible. Lord Shiva said to Vishnu – Don’t be disappointed. The three parts of my body that are now known as Hiranyaksh, Suvarnaksh and Virupaksh Mahadev. Lord Shiva is now worshiped in these three forms as well.
After this Lord Vishnu fought with Sridama and killed him with the Sudarshan Chakra. After this Sudarshan Chakra started living with Lord Vishnu forever.