Bharadwaja was the father of Dronacharya and grandfather of Ashwatthama, who is one among the seven Cheeranjeevins (immortals).
It is believed that Marudwaja Devta found little Bharadwaja abandoned as a baby. They found predicament at the baby's radiant face and adopted him. He was also the adopted son of King Bharata and could be the owner of the whole kingdom but he had no intention to become a king. Young Bharadwaja had an insatiable desire to learn. He spent all his time to understand the Vedas. The Marudwaja gods taught him all they knew about Vedas but Bharadwaja insisted to learn more and to do so he was asked to meditate upon Indra.
Bharadwaja observed rigorous austerity for years, which resulted in the weakening of his body. Eventually he became so weak that he could hardly sit. The Marut gods were filled with pity for him. Finally Bharadwaja fell down meditating when God Indra appeared. Bharadwaja was filled with joy. Indra asked him what would he do if he were given a longer life? Bharadwaja replied that he would again perform meditation and learn more about Vedas. Indra told Bharadwaja that this was his third life and he spent his last two lives in understanding Vedas. Indra then materialized three mountains and took three handful of soil from the mountains. He said to Bharadwaja that three Vedas are like the three mountains and what Bharadwajahas learned is equal to those three handfuls but that did not mean he learnt a little. Even he had gained more knowledge than the gods. Vedic knowledge was endless and gaining the knowledge is important but spreading it is equally important.
Lord Indra then advised Bharadwaja to pray to the trinity God Shiva so that he could perform the yajna, which was equivalent to mastering the Vedas. When Bharadwaja approached the Kailasha, the abode of Lord Shiva, he was busy in the divine dance with Goddess Parvati. Parvati could see the sage but the goddess simply smiled. Bharadwaja had to wait for several days when he was attacked by paralysis and collapsed. Shiva and Parvati noticed this and immediately revived him to consciousness and showered him blessings.
Then onwards Bharadwaja decided to spread the Vedic knowledge among the people and tried to free the society from poverty, disease and war. He traveled far and wide and many kings along with common men became his disciples. Abhayabharati and Divodasa were the most famous among the kings who were the followers of Bharadwaja. He helped the virtuous kings in time of their peril, using his supreme knowledge and with the help of Gods. Bharadwaja's grace helped to achieve a long period of peace and prosperity. The people were happy both physically and spiritually. In his advice his foster parent king Bharata arranged a Yajna and got a son who carried away the heritage line of that great dynasty.
Bharadwaja married Susheela and had a son called Garga, who was also well versed in the Vedas and Upanishads. It is said that when Bharadwaja's time came to an end, the celestial gods showered flowers on the couple. Indra came with a divine chariot to take the pious sage to heaven. Bharadwaja's descendent led the life of Dharma, preaching the world the Vedas, teaching the art of warfare to the pupil and also teaching them the art of administration and life style.
Bharadwaja is also associated with saving his countrymen from the torture of Vaarasikha Demon. The Demon had hundred sons, who were all wicked and avaricious and they constantly harassed people with their large army. They learnt an excellent art of preventing themselves with an invisible protective armors. King Divodasa fought them when they entered the kingdom of Avayavarti. The demonic army entered there, interrupted religious ceremonies, destroyed dwellings, plundered the properties and cut the head of the men; even women and children could not get rid of them.
Divodasa's army assisted Avayavarti's army but they were loosing the battle. They sought shelter in the hermitage of sage Bharadwaja. But the Rishi, who was never angry, denied to give them shelter. He asked the king not to act like cowards but to be brave enough to win the battle so that their countrymen could be saved. He also asked them to sacrifice their body if needed. Bharadwaja then performed Yajna and asked the favor of the gods. His countrymen finally won the battle and they got saved.
There are many people in India, who have Bharadwaj Gotra, who trace their roots to rishi Bharadwaj. They are mainly Brahmins and Kayastha. For century's Bharadwaj descendents have helped maintaining peace and only raised swords when the sins of the earth have reached the climax.