Mooney hired Roy LoPresti to undertake an aerodynamic cleanup of the M20F, resulting in the 1977 model year debut of the M20J. The M20J was marketed under the name Mooney 201 because of its 201 mph (323 km/h) top speed in level flight. The M20J first flew in September, 1976 and was type certified on 27 September 1976.[3][5][9][12]
The improved aerodynamic shape and updated 200 hp (150 kW) engine made the M20J the second most popular variant of the M20 series, after the M20C. It is often used as a training aircraft for commercial pilots. It was originally designed as a private/commercial touring aircraft because of the high cruising speed and relatively low operational cost. This model was marketed as the Mooney 205. The J model had a long production run, lasting until 1998, thus ending the medium body M20 series.