Russell Craig "Rusty" Hamer (February 15, 1947 – January 18, 1990) was an American stage, film and television actor.
 He is best known for portraying Rusty Williams, the wise cracking son of entertainer Danny Williams (Danny Thomas), on the popular ABC/CBS situation comedy "Make Room for Daddy" (later retitled "The Danny Thomas Show"), from 1953 to 1964.
 He reprised the role in three reunion specials and the sequel series, "Make Room for Granddaddy", that aired on ABC from 1970 to 1971.
Samuel Anderson (born 1982) is an English actor.
 He is perhaps best known for playing Danny Pink in the BBC sci-fi series "Doctor Who" and Daniel in the Sky1 sitcom "Trollied".
Tim O'Kelly (born Timothy Patrick Wright, March 12, 1941 – January 4, 1990) was an American actor best known for playing the homicidal sniper Bobby Thompson in the Peter Bogdanovich cult film "Targets" (1968).
 He was cast because of his boy-next-door looks and his similarity in appearance to killer Charles Whitman, on whom the character was loosely based.
 O'Kelly also played Detective Danny "Danno" Williams in the pilot episode of "Hawaii Five-O", but was replaced by James MacArthur.
Claire van der Boom (born 1983) is a Logie Award winning Australian film, television and theatre actress of Dutch ancestry.
 Internationally, she is best known for her appearance as Stella in the HBO miniseries "The Pacific", and her recurring role playing the ex-wife of Det. Danny Williams in the 2010 remake of "Hawaii Five-O".
Spencer's Mountain is an American family drama film written, directed, and produced in 1963 by Delmer Daves from a novel by Earl Hamner, Jr. The film stars Henry Fonda, Maureen O'Hara, and in early appearances in their careers, James MacArthur, Veronica Cartwright, and Victor French.
 Longtime Hollywood actor Donald Crisp plays "Grandpa", his final screen role.
James Gordon MacArthur (December 8, 1937 – October 28, 2010) was an American actor best known for the role of Danny "Danno" Williams, the reliable second-in-command of the fictional Hawaiian State Police squad in the long-running television series "Hawaii Five-O".
Liam Bergin (born 24 November 1985) is a British actor of Irish and Trinidadian descent.
 He trained at the Guildhall School of Music and Drama, graduating in 2008.
 He is currently best known for playing Danny Mitchell in "EastEnders" and Rupert in "Trinity".
 He has also had minor roles in "Doctors" and the 2009 remake of "Minder".
Angela Margaret Cartwright (born September 9, 1952) is an English-born American actress primarily known for her roles in movies and television.
 Cartwright is best known as a child actress for her role as Brigitta Von Trapp in the Academy Award winning film "The Sound of Music" (1965).
 On television, she played Linda Williams, the stepdaughter of Danny Williams (played by Danny Thomas) in the 1950s TV series "The Danny Thomas Show", and Penny Robinson, in the 1960s television series "Lost in Space".
 Her older sister is actress Veronica Cartwright.
David Sheinkopf is an American actor, best known for playing Danny Sharpe during the final (1989–1990) season of the television program "Falcon Crest".
David Judge (born 1983) is a British actor.
 He is best known for playing Danny Valentine in the Channel 4 soap opera "Hollyoaks".

Question: Spencer's Mountain stars an AMerican actor best known for playing Danny Williams in what television series?
Answer: Hawaii Five-O