(born December 24, 1989) is an American professional tennis player.
For one week in August 2016 he was the top-ranked American in men's singles.
He has a career-high ranking of world No.
21.
He has won four ATP Challenger Tour titles and four ATP Tour 250 titles, one at Nottingham on grass, twice at Houston on clay and most recently at Newport on grass.
He won a bronze medal in men's doubles at the 2016 Olympics with Jack Sock.
Johnson was a very impressive collegiate player, playing college tennis for the USC Trojans.
He won the NCAA Men's Singles Championship in his junior and senior seasons (2011–2012), and he was a part of a Trojan team that won four consecutive NCAA Championships.
These accomplishments during his college career cement him as the most-decorated college tennis player ever.