Junior tennis Rhyne was coached by his grandfather, but he went on to train under the USTA Player's Development Program after winning the
Junior Orange Bowl 14s. He was a Top 10 Junior in the world (Career High No.8). Junior Achievements in Singles 2008 US Open Junior Tennis Championships Quarterfinalist 2007 Easter Bowl Champion 2007 USTA International Spring Championships Finalist 2006 Jerry Simmons ITF Junior Circuit – South Carolina Champion Junior Achievements in Doubles 2007 Yucatán World Cup Doubles Champion with
Ričardas Berankis 2007 USTA International Spring Championships Finalist with
Ryan Lipman 2006 Jerry Simmons ITF Junior Circuit – College Station, Texas Champion with
Devin Britton 2006 Costa Rica Bowl Champion with
Blake Davis 2005 Chanda Rubin American Junior Tennis Classic – Georgia Finalist with
Devin Britton Rhyne won the USA F16 in Pittsburgh in 2007 at the age of 16 years and 3 months, which made him the youngest U.S. male to win an
ITF Men's Circuit event in the United States (however, stats for this are held since 1998). After winning the title, he focused on the pro circuit and didn't play any junior event in 2008 until the US Open Junior Tennis Championships (last junior tournament of his career). Past coaches include Michelle DePalmer-Williams, Mike DePalmer Sr., Mike DePalmer Jr., Dustin Taylor, Andres Pedroso, Martin Van Daalen. Since claiming his 1st futures title in 2007, Williams couldn't handle the pressure of turning pro and decided to go to college, "I guess the main reason I went to school was to mature," he recalls. "It gave me a chance to get away from the pressure. I was thinking about it and I started to kind of hating tennis for a while, and I wanted to get away from the pro tennis deal. So I went to school, matured, and started enjoying tennis again."
College Williams played two years of college tennis for his hometown Tennessee Volunteers in
Knoxville, Tennessee, under head coach
Sam Winterbotham and associate head coach
Chris Woodruff. He enjoyed one of the best two seasons of any player in program history with accomplishments including: All-America honors in 2010 and 2011, earning the No. 1 national singles ranking in 2011 and reaching the 2011 NCAA Singles Championships. He finished his career with an 83–17 singles and 66–14 doubles record. With his family history, Williams was a sensible fit to the Tennessee program. His grandfather,
Mike DePalmer Sr., is the most successful head coach in Volunteer history, and his mother and uncle were both All-Americans in Knoxville. He started out his career with a splash, earning 2010
Southeastern Conference Freshman of the Year honors and helping the team to the NCAA finals. He became one of the top singles players in the country as a sophomore in 2010–11. He defeated
Steve Johnson of the
University of Southern California in the finals of the 2010 USTA/ITA National Intercollegiate Indoor Championships to become the third Tennessee player in program history to win the event. The victory boosted Williams to No. 1 nationally in the ITA singles rankings the following January. Williams played at the No. 1 and 2 singles positions during the team season and played doubles with fellow Tennessee native
Tennys Sandgren. He concluded his college career by reaching the final of the 2011 NCAA Singles Championship, this time losing to Johnson in three sets.
Early professional Williams played in his first
Futures tournament in 2006, and won his first tournament in Pittsburgh in July 2007, aged just 16. His reached 782 in the ATP rankings in November 2007, a position he would not better until August 2010. He entered his first tournament at the
ATP Challenger level at the
Fifth Third Bank Tennis Championships in 2008, but competed mainly in Futures tournaments until 2011. During this time, Williams struggled with his weight. The second half of 2011 saw Williams compete more regularly at the Challenger Tour, and in the qualifying for the
2011 US Open. He ended the year ranked 510.
2012 2012 was Williams's breakout year. In March 2012 he was a surprise qualifier for the
2012 Indian Wells Masters, taking a set from world number 86
Frederico Gil in his first
ATP World Tour level match. He subsequently made two quarter-finals in Challenger tournaments, entering the top 300 for the first time. His next major success came in qualifying for the
2012 US Open, his first appearance at
Grand Slam level. Here, Rhyne lost to former champion and 20th seed
Andy Roddick in straight sets. He achieved his best result in a Challenger tournament at the end of the season, reaching the semi-finals at the
JSM Challenger, ensuring that he would end the year ranked in the world top 200. His final tournament of 2012 saw him obtain qualification for the
2013 Australian Open.
2013 Winning the Australian Open Wildcard Playoff, Williams qualified to the main draw of the Australian Open. However, he lost to the 25th seed Florian Mayer 6–2, 6–3, 2–6, 6–7(12–14), 1–6. Next, Williams reached the second round of the Maui Challenger. In the same tournament for doubles, Williams partnered with former college partner Tennys Sandgren, and they reached the finals before losing a third-set super-tie breaker. Williams then played in the Dallas Challenger, and won his first challenger tournament defeating Robby Ginepri in the finals. Williams gained 100 points and had defeated Austin Krajicek, Rajeev Ram, Alex Kuznetsov, and Frank Dancevic on his way to the finals. In the same tournament for doubles, Williams partnered once again with Sandgren, and they reached the finals before once again losing a third-set super-tie breaker. In the U.S. National Indoor Championships, Williams won two qualifying matches to reach the main draw. In the first round, Williams gained his first ATP win over former college rival, Steve Johnson, defeating him 7–6(7–4), 6–4. In the second round, Williams fell to 7th seed Alexandr Dolgopolov 4–6, 6–4, 4–6. Williams gained 65 points from this tournament, therefore reaching a career high ranking of 133, as well as attaining a career record of 1–4. Williams made his first career ATP semifinal at the
U.S. Men's Clay Court Championships in Houston, defeating Pella Guido, Ivo Karolvic, and Ruben Ramirez Hidalgo before falling to World No. 12, Nicolas Almagro. He earned entry into the main draw of the
2013 French Open as a "Lucky Loser." Williams entered the tournament ranked a career-high 117th in the ATP. Williams lost in his French Open debut and FQR of
2013 Wimbledon (his first grass season). Williams made his first ATP Doubles Final partnering Tim Smyczek at
Hall of Fame Tennis Championships. Williams struggled with shoulder injury and didn't fare well in the USO summer hardcourt swing. He received a wildcard into the
2013 US Open and lost in the 1st round to Nikolay Davydenko despite having a double-break lead in the 4th set 3–6, 6–4, 6–1, 5–7, 0–6.
2014 Williams qualified for the
2014 Australian Open. In the main draw, he lost against fifth seed
Juan Martín del Potro, winning the first set. ==ATP career finals==