Children: son Keen (b. June 2001) and daughters Bella Noche (b. May 2005) and Odette (b. October 20, 2007).
He was set to appear in Signs (2002) but had to drop out when he was diagnosed with a brain tumor. His part in Signs (2002) went to Joaquin Phoenix. The brain tumor Mark was diagnosed with was found to be benign. Following brain surgery, he has fully recovered after suffering from a partial facial paralysis.
He was diagnosed with a benign brain tumor (more specifically, an acoustic neuroma) in 2002; he subsequently had it removed and is in good health.
While appearing in the drama "Awake and Sing!", he was nominated for the 2006 Tony Award (New York City) for Supporting or Features Actor in a Drama.
He was supposed to play the part of "Perry Smith" in Infamous (2006) but had other engagements and so recommended Daniel Craig, who then went on to get the job.
His brother, Scott Ruffalo, died December 8, 2008, after being found outside his Beverly Hills home after a gunshot wound to the head. He was a 39-year-old hairdresser and was married to Luzelena. His body was cremated.
Sold his L.A. home in 2009 and moved his family to Callicoon, New York.
Sold his three-bedroom, 2,957-square-foot house in Los Angeles' Hollywood Hills for $1,650,000. He bought the property in 2004 for the same price for which he later sold it.