This idiom means to gain an advantage or head start, often through assistance, opportunity, or strategic positioning. It suggests being boosted to a higher position, like getting a leg up over a fence, and is used in competitive, professional, or personal contexts to describe achieving a favorable edge. The phrase carries a positive, opportunistic tone, reflecting cultural values of ambition and resourcefulness, but can also imply reliance on external help or privilege, depending on context.

The phrase likely originated in 19th-century Britain or America, tied to the literal act of helping someone climb by offering a ‘leg up,’ such as in horseback riding or scaling obstacles. An early use appears in an 1837 *Knickerbocker Magazine* article, describing a student ‘getting a leg up’ through tutoring. The idiom gained traction during the Industrial Revolution, reflecting competitive economies, as seen in Charles Dickens’ *Great Expectations* (1861). Its use grew in American English during the 20th century, particularly in business and sports, and spread through media and literature. The phrase’s vivid imagery and relevance to advancement ensured its enduring use, especially in contexts of opportunity and success.