Justin Jeremy Gimelstob (born January 26, 1977[2]) is a retired American tennis player.

[5] In singles matches, he defeated Andre Agassi,[6] Petr Korda,[7] Àlex Corretja,[8] Pat Rafter,[9][10] and Gustavo Kuerten.

[15] As a sophomore at Newark Academy, Gimelstob led the school's tennis team to a 26–0 record and won the state Tournament of Champions.

In September 1995, when he defeated David Prinosil in the first round of the U.S. Open it was stated in Sports Illustrated.

[21] At the US Open, 5' 9" Michal Tabara was fined $1,000 for unsportsmanlike behavior for spitting at Gimelstob after their match.

In doubles, he and Jeff Tarango lost in the 2nd round to Brian MacPhee and Nenad Zimonjić, 7–5, 2–6, 6–7 (5–7).

At Wimbledon 2004, Gimelstob and Scott Humphries defeated Bob and Mike Bryan 6–3, 3–6, 6–4 in the second round.

[21] In July 2004, Gimelstob won in singles at Forest Hills, New York, beating Dušan Vemić 7–6 (7), 6–2 in the final.

That September, he beat Florent Serra of France 6–2, 6–2 in the quarterfinals, and Alex Bogomolov Jr. 6–1, 6–3 in the final of a hard court tournament in Beijing.

[21] In 2006, Gimelstob reached his first ATP Tour Singles Final at The Hall of Fame Championships in Newport, Rhode Island, losing to Mark Philippoussis.

In September 2006 he had back surgery to remove two large disc fragments that were putting pressure on the nerves to his right leg, causing him to lose sensation.

[24][25] In June 2007, Gimelstob lost a contentious 6–4 vote of the ATP Players Council in his attempt to replace Andre Agassi's manager, Perry Rogers, on the men's tour's 3-man board of directors, and to become the first active player on the board.

[29][30][31][32] He was an assistant coach of Team USA's tennis squad at the 1981 Maccabiah Games in Israel.

[38] Gimelstob was a blogger for Sports Illustrated (under the name "Gimel Takes All"), and served as a regular commentator for Tennis Channel.

[41] On May 1, 2019, Gimelstob resigned from the ATP Player Council after a series of controversies (see below) and subsequent pressure from Stan Wawrinka[42] and Andy Murray.

[43] John Isner hired Gimelstob as his new coach at the end of the 2014 season[12] and worked with him until April 2016.

[45] Also in 2008, Gimelstob told Out Magazine: "The locker room couldn't be a more homophobic place.

There's just a lot of positive normal hetero talk about pretty girls and working out and drinking beer.

"[46] In 2016, Gilmelstob's wife Cary sought a restraining order against him, alleging that he "physically assaulted, harassed, verbally attacked, and stole" from her.

[48][49] In November 2018, Gimelstob was charged with assault after being accused of repeatedly striking Randall Kaplan while the venture capitalist, his wife and their two-year-old daughter were trick-or-treating on Halloween in West Los Angeles.

[59] Gilmelstob later changed his plea to "no contest" to a felony battery charge, and was sentenced to three years’ probation and 60 days of community labor.