Like a number of those at the court of England's King Henry VII and his son, King Henry VIII, Nicholas Carew was born into a well-connected noble family and placed in the household of the king at an early age.

Nicholas came to court at the age of six, and grew up with the younger Henry, sharing the latter's education. Part of that education included fencing and jousting, and both young men grew up to be experts in both forms of battle. Nicholas was particularly adept at jousting, and made a name for himself in the sport. He was well-known for his fearlessness, and became so proficient and popular in the sport that the king provided him his own tiltyard. He received a knighthood before he was twenty years old.

Nicholas remained popular with Henry VIII, and the two spent much time together. Like the king, he was known for being a ladies man; indeed, he was known as something of a rake in his youth. Cardinal Wolsey believed that he had far too much influence over Henry, had Nicholas returned again, but then Wolsey sent him away yet again, this time to France, and in 1526 he organized his removal from the Privy chamber.

Despite Wolsey's strenuous efforts, Nicholas was named Master of the Horse, a position particularly close to the king and his day-to-day life. He held the position until his death. During the 1520s, Henry sent him on embassies to France, where he negotiated English relations with King Francis I. The French king became fond of him, and encouraged Henry to continue to support Nicholas and his career. Then, in early 1528, much to the dismay of Wolsey, Nicholas was restored to the Privy chamber.

It is possible he regained such a lofty position due to the influence of his cousin, Anne Boleyn. Despite her likely assistance, Nicholas was not happy with Anne's behavior and influence over Henry. He favored Queen Catherine and the Princess Mary, though did not openly support them. By 1531, Nicholas was so angry with Anne Boleyn that he began to work against her, eventually contributing to her downfall.

During this time, Nicholas married the sister of Sir Francis Bryan (also a cousin of Anne Boleyn, who contributed to her downfall), Elizabeth. Nicholas continued for a while to remain in Henry's good graces, but when Thomas Cromwell presented Henry with letters written by Nicholas that were apparently treasonous, the king was persuaded that he was involved in the Exeter Conspiracy, a plot rumored to depose him. Nicholas was arrested and executed in 1539.