Țiriac was married to Erika Braedt, a handball player, between 1963 and 1965.

He was born in Transylvania, which is probably the reason why he has the nickname 'Count Dracula'. Țiriac first appeared on the international Sports scene as a child ping pong champion, then subsequently as an ice hockey player on the Romanian national team at the 1964 Winter Olympics. Shortly after that he switched to tennis as his main sport. With fellow Romanian Ilie Năstase he won the men's doubles in the 1970 French Open and reached the Davis Cup finals several times in the 1970s.

Tiriac participated in the short period during the 1970s when women dabbled as coeds in established men's tennis tournaments. In his first match he defeated Abigail Maynard 6-0 6-0 in their round one match at USTA pro circuit's Fairfiled County International Tennis Championship. It was the first time ever a female had entered a men’s tournament.

He became the Sports agent of Boris Becker and managed his career from 1984 to 1993. In 1998 he became President of the Romanian National Olympic Committee.

After his retirement as a professional tennis player, Țiriac became a businessman in Germany. In 1987, he appeared in a TV commercial for Miller Lite beer with Bob Uecker, who extols Țiriac's supposed humorous qualities, laughing hysterically while Țiriac sits stone-faced.

Following the collapse of communism in Romania, he started numerous businesses and Investments back home. In 1990, he founded Banca Țiriac, the first private bank in post-Communist Romania. Between that and several other enterprises (retail, insurance, auto leasing, auto dealerships, airlines, etc.), his fortune was estimated at over US$900 million in 2005.

Țiriac also holds the license for the BRD Năstase Țiriac Trophy tennis tournament since 1996. It is currently a €450,000 event, part of the ATP World Tour 250 series, held annually in Bucharest, Romania, just 2 weeks before the Madrid Open.

Ion Țiriac became the first Romanian to enter Forbes' List of billionaires in the 2007 Forbes rankings, ranking 840th in the world. His wealth was estimated at $1.0 billion as of 2010, according to the magazine. In 2010, TOP 300 Capital declared Ion Țiriac the richest man in Romania with a wealth estimated at €1.5–€1.6 billion ($2–$2.2 billion).

In 2012 he was nominated for the ITF Hall of Fame in the contributor category.

On 13 July 2013 he joined the ITF Hall of Fame as a successful promoter and tournament Director for numerous events including the two of the largest Masters 1000 events, the Italian Open and the Madrid Masters.

Ion Țiriac is a car collector. Tiriac Collection represents the exhibition of cars and motorcycles of Mr. Ion Tiriac. Reopened to the public in May 2015, the collection includes over 300 historical vehicles manufactured since 1899 and also modern exotics with about 165 cars displayed at all times.Visitors will find the only collection in the world with the 6 Rolls Royce Phantom produced until 1972, as well as exhibits that previously belonged to great names such as Sir Elton John, Sammy Davis Jr. or Bernie Ecclestone.