When Jenner & Block leaders contemplated starting the private wealth practice the firm announced last week, one proponent of the idea may have helped sway them more than others: Lester Crown, the 90-year-old Chicagoan and patriarch of one of America’s wealthiest families.

Jenner & Block has for decades represented the Crown family as well as General Dynamics Corp., the defense contractor in which the family has held a large and sometimes controlling interest dating back to the 1960s. General Dynamics remains a large portion of the family’s $8.8 billion fortune as estimated by Forbes last year.