Once, a king by the name of Kaartaveerya-arjuna visited the hermitage of Jamadagni, along with his army during the course of a hunting trip in the forest. Jamadagni arranged to feed his guest and his vast army with the help of his divine cow. Amazed at this, the king became greedy and wanted the cow to be given to him. Jamadagni refused, saying that the cow is required in the performance of religious rites. The king sent his soldiers and forcibly took the cow away to his city. Hearing this, Parasurama went to the king's place and destroyed his army and finally killed the king with his axe. In retaliation, the sons of Kaartaveerya-arjuna killed Jamadagni by beheading him while in meditation and at that time Parasurama was not at home.
Parasurama became very furious upon hearing of his father's death and to avenge his killing, he not only killed all the sons of Kaartaveerya-arjuna but also rooted out the entire royal clan. He thus conquered the entire earth and gave it away in charity to Kasyapa after performing final rites of his father. Parasurama is one of the eight Chiranjeevins (immortals).
According to one legend, when Parasurama went to visit Shiva, he was denied access by Ganesha. Parasurama threw his axe at him, and recognizing the weapon as that given by his father, Ganesha permitted it to sever one of his tusks as he waited to receive it.
When Vishnu incarnated as Rama (the hero of Ramayana), Parasurama had to submit before him as his avataara-kaarya (mission) was over. He then surrendered to Rama, gave away all his punya-lokas (the fruits of his good deeds) to Rama and became an ordinary saint, and is said to be still living on Mahendra parvata, spending time in penance, as he is a Chiranjeevi. It is said that Parasurama will become one of the Saptarishis (seven great saints who will direct the mankind towards dharma) in the next Manvantara.