Mark is a Cedar Rapids, Iowa native and Graduate of Cedar Rapids Jefferson High School. In 1996, he co-founded the Liberty Hampshire Company, LLC with Steven E. Johnson, in Chicago. In 2000, he helped found Guggenheim Partners, LLC. Today, he is the chief executive officer of Guggenheim Partners, which has rapidly grown into a global, Diversified financial services firm with more than $260 billion in assets under management, 2,300 employees, and 25 offices in six countries around the world.
On December 10, 2012, in its annual survey of the "50 Most Influential People in Sports Business," the SportsBusiness Journal named Walter the 8th most influential person in Sports Business due to the historic Dodgers purchase.
Walter and several of his partners also bought the Los Angeles Sparks basketball team in 2014.