Both his grandfather and father (Clarence J. Brown, Sr. & Jr.) were United States Representatives from the 7th District of Ohio. Clarence Sr. served from 1939 to 1965; Clarence Jr. from 1965 to 1983. Both were also candidates for governor of Ohio, both unsuccessful.
Is a patron of the Beth Brown Memorial Fund, a scholarship programme designed to assist poorer students who wish to study in the field of paediatric healthcare. The charity is in honour of his elder sister who died in childhood of leukaemia in 1964. It has since expanded to also offer the Clarence J. Brown Scholarship for students interested in pursuing careers in government and public service as well as the Robert Townsley Scholarship for students of journalism.
Although his character Rawhide dies in The Adventures of Buckaroo Banzai Across the 8th Dimension (1984), he is still under contract to appear in a sequel to the film.
According to the trivia track on the DVD of The Adventures of Buckaroo Banzai Across the 8th Dimension (1984), his character, Rawhide, did not die but went into a deep coma, and that he was expected to recover very soon.
Was hospitalized after becoming sick from the prosthetic make up he wore as Viktor in The Bride (1985). He was reluctant to don prosthetics for his role in Highlander (1986).
Due to his role of Kurgan in Highlander (1986), his voice was featured on the Queen song "Gimme The Prize (Kurgan's Theme)". An alternate version appeared in the film itself, but samples of his voice are included on the 1986 studio album "A Kind of Magic".
For Highlander (1986), he said that he made a lifelong friend in Bob Anderson, the swordmaster for that film as well as the "Star Wars" trilogy. He said if he hadn't been an actor, he would have been (in order) a fireman, an aristocrat, an archaeologist/anthropologist, a scuba diver, and a circus acrobat.
Both he and Highlander (1986) co-star Christopher Lambert have portrayed the Mortal Kombat character Rayden. Lambert played Rayden in the film Mortal Kombat (1995), while Brown portrayed Rayden in the TV series "Mortal Kombat: Defenders of the Realm" (1995).
In 1999 he spearheaded a charity campaign to raise funds for J. Madison Wright, the young girl who played his screen daughter in the TV show "Earth 2" (1994). Madison, then aged 15, had developed cardiomyopathy and was in dire need of a heart transplant, a very costly operation which exceeded her family's lifetime health insurance policy. Clancy offered to assist the Wrights in their plight. He also bought young Madison a laptop computer for Christmas in 1999. Tragically, Madison died seven years later, in July 2006, of a heart attack.
Has played two characters named Capt. Hadley: The Guardian (2006/I) and The Shawshank Redemption (1994).
Has three times played senior prison officers in movies dealing with miscarriages of justice: in The Shawshank Redemption (1994), the tyrannical Capt. Hadley; in The Hurricane (1999), the sympathetic Lt. Williams; and in Last Light (1993) (TV) as Lt. McMannis.
Daughter Rose Beth Brown (born in October 1995). He also has a son born in 2003.
Originally auditioned for the role of Superman/Clark Kent on Bruce W. Timm's "Superman" (1996) The Animated Series, but Timm felt his voice was better suited to Lex Luthor, bringing the arch villain a smooth combination of menacing brute and charming manipulator. Tim Daly was then cast as Superman/Clark Kent instead.
He has played the same character (Lex Luthor) on four different series: "Superman" (1996), "Justice League" (2001), "The Batman" (2004)_ and "The Life and Times of Juniper Lee" (2005).
On August 20, 2002, he was named chairman of the board of Brown Publishing, a newspaper company owned by his family. He has been a board member since 1987.
Profiled in "Character Kings: Hollywood's Familiar Faces Discuss the Art & Business of Acting" by Scott Voisin. 
Designated as a Significant Sig by the Sigma Chi General Fraternity in 2010.