Dixon, a 6-2 guard from Delaware, averaged 16.5 points and shot 37.0 percent from 3-point range en route to earning MAAC Rookie of the Year honors. He scored at least 20 points in 10 games as a freshman.
Dixon will have three years of eligibility remaining after sitting out the 2017-18 season.
St. John's has reeled in several Division I transfers since Chris Mullin took over two years ago. Tariq Owens (Tennessee) averaged 5.2 points and 5.2 rebounds this past season, while Justin Simon (Arizona) and Marvin Clark (Michigan State) will become eligible next season.