How Well Do You Know English Slang?
the good life, an easy and pleasant life or carefree existence
most likely from Patric Rooney's 1880 song "Is That Mr. Reilly"
"life at ease," expression popularized by 1917, American English, sometimes said to trace to various songs from c.1902.
A life of luxury: “Sheila found herself living the life of Riley after she won the lottery.” The expression comes from a popular song of the 1880s, “Is That Mr. Reilly?”, in which the title character describes what he would do if he suddenly became wealthy.