I learned a great deal about improv from two teachers---Martin Harvey Friedburg and Del Close---both who started as actors with The Second City in Chicago. Since its debut in 1959, the Second City has consistently been a starting point for comedians, award-winning actors, directors, such as Bill Murray, John Candy, Tina Fey, Amy Poehler, Steve Carell, Stephen Colbert, and Cecily Strong among many hundreds of others.
In this podcast, Second City improv school folks talk about improv and business---great tips for lawyers, also.