<human>: William George Meany (August 16, 1894 - January 10, 1980) was an American labor union leader for 57 years. He was the key figure in the creation of the AFL-CIO and served as the AFL-CIO's first president, from 1955 to 1979. Meany, the son of a union plumber, became a plumber at a young age, as well. He became a full-time union official 12 years later.

Meany was born into a Roman Catholic family in Harlem, New York City on August 16, 1894, the second of 10 children. His parents were Michael Meany and Anne Cullen Meany, who were both American-born and of Irish descent. His ancestors had immigrated to the United States in the 1850s. His father was a plumber and a strong supporter of the trade union movement and served as president of his plumber's union local. Michael Meany was also a precinct level activist in the Democratic Party.  Meany grew up in the Port Morris neighborhood of The Bronx, where his parents had moved when he was five years old. Always called "George," he learned that his real first name was William only when he got a work permit as a teenager. Following his father's career path, Meany quit high school at 16 to work as a plumber's helper. He then served a five-year apprenticeship as a plumber and got his journeyman's certificate in 1917, with Local 463 United Association of Plumbers and Steamfitters of the United States and Canada.  His father died suddenly of a heart attack in 1916 after a bout of pneumonia. When Meany's older brother joined the US Army in 1917, George became the sole source of income for his mother and six younger children. He supplemented his income for a while by playing as a semiprofessional baseball catcher. In 1919, he married Eugenia McMahon, a garment worker and a member of the International Ladies Garment Workers Union. They had three daughters. CANNOTANSWER

Using a quote from the above article, answer the following question: what was his biggest accomplishment?
<bot>: got his journeyman's certificate in 1917, with Local 463 United Association of Plumbers and Steamfitters of the United States and Canada.