Sébastien René Grosjean (French pronunciation: [sebastjɛ̃ ʁəne ɡʁoˈʒɑ̃]; born 29 May 1978) is a retired tennis player from France. His career-high ATP singles ranking was World No. 4, achieved in October 2002. Grosjean retired from tennis on 27 May 2010.
Grosjean joined the professional tour in 1996. In 2003 and 2004 he reached the final of the Queen's London Tournament. In the same two years, he also reached the semi-finals of Wimbledon. He finished 2001 as the No. 1 player from his country and for the first time in the top 10 becoming the first Frenchman to finish a year in the top 10 since Cédric Pioline in 1993. In 2001, Grosjean won the Davis Cup with the French team.
Grosjean is known for his extreme forehand, his best shot, he utilizes something of a western grip, which is hit at high velocities. He has appeared in four Grand Slam semifinal matches. As well as his two Wimbledon runs, he also reached the French Open semi-finals in 2001. His most famous chance was at the 2001 Australian Open against Arnaud Clément. Grosjean led two sets to love and had a match point in the fourth set before Clément prevailed. This was long considered the worst 'choke' in five-set history, until the 2004 French Open final.
He won his fourth singles title at the 2007 Grand Prix de Tennis de Lyon, with a 7–6, 6–4 victory over countryman Marc Gicquel. He also won the doubles final with Jo-Wilfried Tsonga (who Grosjean beat in the singles semifinals), entering the tournament as a wildcard team where they upset the first and third seeds. They beat Łukasz Kubot and Lovro Zovko 6–4, 6–3 in the final, and the Kubot-Zovko team was the only team that was not all-French.
Considered one of the more popular players on the circuit, he is lauded for his attractive, graceful style and classical skills. He is affectionately nicknamed 'Big John' by fans, a literal translation of his surname into English.
Grosjean married his wife Marie-Pierre on November 16, 1998 and has a daughter named Lola (born October 11, 1998), a son named Tom (2002) and a daughter named Sam (2006). The family currently resides in Boca Raton, Florida, United States, where Grosjean trains at the Evert Tennis Academy. He is sponsored by Lacoste in apparel and Head rackets. He used the Head Prestige Classic 660 throughout his career.