The Mediterranean estate has a five-bedroom, 4 1/2 -bathroom house containing 4,605 square feet of living space.
Inside, the dramatic two-story entry has a sweeping staircase.
Conrad starred in the TV series "The Wild Wild West" (1965-69) as Secret Service agent James T. West, a role for which he won a spot in the Stuntman's Hall of Fame. He also appeared in the series "Baa Baa, Black Sheep" (1976-78), "A Man Called Sloane" (1979) and "High Sierra Search and Rescue" (1995).
The property previously sold for $1,975,000 in 2006, public records show.
Buyer has landed in Sunset Strip
Update: Film and TV producer David Niven Jr. has sold his Sunset Strip-area home for $5 million.
The contemporary Mediterranean, built in 1967, has six bedrooms and seven bathrooms in 6,600 square feet. There are high ceilings, skylights, a library and city-light views.
The living room opens to a swimming pool, an outdoor entertainment area and rose gardens.
Niven, 67, has a dozen producing credits, including the 1976 classic "The Eagle Has Landed."
He is the former head of the William Morris Agency for Europe and the former head of production for Columbia Pictures and Paramount Pictures based in London.
The eldest son of Academy Award-winning actor David Niven Sr., he played the British foreign minister in "Rush Hour 3" (2007).
The house came on the market in May at $5.75 million. The property previously sold in 1983 for $1.2 million, according to the MLS.
Joyce Rey and Debra Smalley, both of Coldwell Banker, Beverly Hills, were the listing agents. Andrea Pintar of Nourmand & Associates, Beverly Hills, represented the buyer.