Lampert launched ESL Investments in 1988 with $28 million in seed capital from Texas investor Richard Rainwater, establishing a track record of aggressive value investing that generated 46x returns by 2003. His most celebrated win came from acquiring 30% of AutoZone, where hands-on due diligence and stock buyback strategies turned a $20 per share entry into a $500-600 per share exit worth approximately $1.5 billion. After engineering the 2005 merger of Kmart and Sears, Lampert oversaw ESL's acquisition of bankrupt Sears for $5.2 billion in 2019, subsequently extracting value through spinoffs including Lands' End and the real estate-focused Seritage Growth Properties. Now operating from Miami's Indian Creek Island, Lampert continues directing ESL Investments' concentrated portfolio with approximately 15 employees, maintaining full approval authority over every investment decision.