Alexander Mitchell was an immigrant from Aberdeenshire, Scotland who came to Milwaukee in 1839 to enter the insurance business. The company eventually evolved into a bank, and Mitchell became a powerful banking executive. Mitchell also served in congress and was nominated to run for governor, but declined the nomination.
Mitchell also became involved in railroading, taking over the nearly bankrupt Milwaukee & St. Paul Railroad. Under his leadership, it grew into the Chicago, Milwaukee & St. Paul Railroad. (It would one day become the enormous Milwaukee Road.)
Mitchell built an estate on Grand Avenue that today is the Wisconsin Club. He is the namesake of Mitchell Street, Mitchell Park, Alexander Mitchell Integrated Arts School, Alexander Mitchell Public Library in Aberdeen, South Dakota, Mitchell South Dakota and, of course, this building. Mitchell also built the Mackie Building which shares the East 200 block of Michigan Avenue.
His son, John L. Mitchell was a congressman and his grandson, General William "Billy" Mitchell is considered the father of the modern air force. (He is the namesake of Milwaukee's General Mitchell International Airport, referred to by Milwaukee residents as "Billy Mitchell Field." The B-25 Mitchell bomber was named in his honor, the only such air force aircraft named for a person.)
It wasn't all work, though. Mitchell was an avid fan of curling, and founded the Milwaukee Curling Club in 1840 and was prominent in the Grand National Curling Club.
Alexander Mitchell is buried in the Mitchell family plot at Milwaukee's Forest Home Cemetery.