Born and raised in Gallatin, Tennessee, he went on to play two years of college tennis at the University of Tennessee before launching his professional career. Junior 9 in the combined International Tennis Federation junior world rankings in April 2009. Junior Slam results:
Australian Open: -
French Open: 3R (2009)
Wimbledon: 2R (2009)
United States Open: 2R (2009)
College Sandgren was a January midseason addition to the Tennessee Volunteers" 2010 tennis roster, joining older brother Davey, who was a senior All-American on the team
Coached by Sam Winterbotham and Chris Woodruff, the younger Sandgren immediately strengthened the middle of the Vols" singles lineup, going 10-0 in Southeastern Conference play at the Number.
The team went on to reach the National Collegiate Athletic Association team finals that year as well. As a sophomore, Sandgren reached the semifinals of the National Collegiate Athletic Association Singles Championships, losing to teammate, roommate and doubles partner Rhyne Williams in three sets.
He finished the season with a 37-6 record and his 10-1 record in conference once again helped the Vols to an Securities and Exchange Commission regular-season title. He finished his career with a 60-12 singles record (833), the third-best career winning percentage in Tennessee history.
Sandgren turned pro in 2011, reaching his highest Association of Tennis Professionals singles ranking of World Number.
209 in April 2013 and his highest Association of Tennis Professionals doubles ranking of World Number. 137 in February 2013. Singles (1)