The NACA 4 digit series were developed by systematic variation by Eastman Jacobs. They were inspired by the German Gottingen Go series, the first modern thick wing airfoils. Eastman Jacobs then went on to develop the NACA 5 digit series by systematic variation of the upper leading edge, these gave slightly higher coefficients of lift and L/D ratio at the expense of slightly inferior stall characteristics.
The Germans used both the NACA 4 and 5 and the allies used the Go (Sunderland flying boat, Sterling). The Germans developed a way of describing the modifications of the NACA series (those 2R numbers) which were then copied by the NACA. EG the B-58 Hustler airfoil.
Willy Messerschmitt developed improvements to airfoils that gave them good pitching characteristics and improved aircraft stability and stall characteristics, his academic fame probably rests on that.
Eastman Jacobs went on to develop the NACA 6 series laminar flow series of airfoils and those of the P-51. These were the first ones to be developed by formulae rather than systematic tests in a wind tunnel. Jacobs airfoils had good transonic and supersonic characteristics and he was developing a supersonic aircraft called Jakes Jeep. It used a motorjet. This is why the Bell X1 had straight wings.
When he found out about the Turbojet in 1943 and that the NACA had been kept out of the loop by USAAF it broke his heart and he quit and opened a seafood restaurant. The Bell air comet was probably a failure because of a lack of involvement by Jacobs.