Began playing tennis at age 8 when he found his mother’s racquet.
Has won 3 Grand Slam doubles titles, his first alongside Vasek Pospisil at Wimbledon in 2014, then back-to-back titles with Mike Bryan at Wimbledon and US Open in 2018. The pair also went on to win the 2018 Nitto ATP Finals.
Has a career-high ranking of No. 2 in doubles (achieved September 2018) and No. 8 in singles (achieved November 2017).
14 Career ATP Doubles Titles.
4 Career ATP Singles Titles.
At the 2016 Olympic Games in Rio de Janeiro, he won the gold medal in mixed doubles alongside Bethanie Mattek-Sands, and a bronze medal in men's doubles with Steve Johnson.