At first, he was not considered a great musician. (The ancient bards were supposed to have started their training when they were still young children and Carolan didn't start until he was an adult.) One of his first patrons, a Squire Reynolds, suggested that he try his hand at composition. His first work, "Si Beag, Si Mor", resulted from this suggestion. After he finished the composition, his fame was spread throughout all of Ireland and he started his career.

The way Carolan made his living, was to travel from big house to big house, from castle to castle, entertaining the households and the friends of some of the most famous and wealthy people of Ireland at the time. Often, as a special favor, he would write a tune in honor of the man of the house, or his wife or daughter. He called these tunes "Planxties". He was very successful and people would often delay weddings and funerals until he could be present to play the appropriate tune.

When Carolan was a very young man, before his blindness, he met and fell in love with a young woman named Bridget Cruise. Bridget was part of a noble family and Carolan's family was of skilled laborers, so a match could never be made. And even though he went on to live a very successful life, he never forgot Bridget and wrote 3 planxties in her honor. He met her again near the end of his life, when he was on his way to a religious retreat in County Donegal. He happened to touch a woman's hand and instantly recognized that it was hers.

Carolan was also famous for his love of drink, especially Irish whiskey. He wrote a tune in honor of whiskey. As he was dying, he called for one last cup of his favorite brew. His dying words were said to be "the drink and I have been friends for so long, it would be a pity for me to leave without one last kiss." And he died.