He created and directed a number of major corporations with a wide range of products for the automobile and aviation and related industries.
It produced a wide variety of automobile parts, such as transmissions, gears, springs, bumpers, and especially axles for trucks, buses, streetcars, tractors and other motorized vehicles.
"[4] Rockwell became interested in aviation after the war, and produced a wide variety of engine parts, as well as a small executive aircraft.
Sales reached $6.3 billion in 1979, ranking it number 11 in defense contracts, in addition to its major presence in commercial aircraft, electronics, automotive components.
Rockwell came from a Yankee family and married Clara Thayer, a descendant of John Alden who arrived aboard the Mayflower in 1620.
Rockwell Jr. became a senior executive for several of them before taking over in the mid-1960s, leading work on the NASA Apollo and Space Shuttle programs until his 1989 retirement.
Willard Sr. also brought his brother Walter F. Rockwell (1899-1973) into the family business, making him president of Timken-Detroit Axle 1933 to 1953, as well as other roles.