Borg won two straight sets, 6-4, 6-4, to defeat Ross Weibull on Sunday to take home the junior title for the second year in a row.
Last year, Borg won both the singles and doubles national championships for 14-year-olds.
So far this year, Borg has won the indoor Salk Open junior championship, placed second in the indoor national championship and second in the Båstad junior championship.
“Clearly Leo is someone we believe strongly in and who we're going to work hard with so he can develop further,” his coach Rickard Billing told daily Aftonbladet.
“We're taking one day at a time, working hard. We feel he's doing well.”
Leo Borg resembles his father with his tall, lean frame, long blond hair, and blue eyes.
Borg senior won 11 Grand Slam titles, including five Wimbledons, and was ranked world number one for 109 consecutive weeks from 1979 to 1981.