Williams was born on September 30, 1954 in Santa Monica, California. He grew up near actor Peter Graves. As a young child, he constantly asked Graves for show biz advice. At age 11 Williams changed his name from Barry William Blenkhorn to Barry Williams and hired an acting coach. He also took acting classes to learn film and television techniques.Williams quickly landed a lead role in an educational school film entitled "Why Johnny Can't Read." Williams later made his television debut in an episode of Dragnet in 1967. He followed up with small roles in other television shows, such as "Gomer Pyle" and "The Mod Squad." In 1969 Williams acquired his role as Greg Brady on The Brady Bunch and became a big television star and heartthrob for teenage girls.

The Brady Bunch was a family sitcom about a blended family - a man ("Mike Brady" - played by Robert Reed) with three boys married a woman ("Carol Brady" - played by Florence Henderson) with three girls. After marriage, they moved in together as a big, happy family. Greg Brady was the oldest male child on The Brady Bunch and was an integral character on the show. The show dealt with, among other things, Greg Brady's teenage angst and his chasing of girls.
The child actors on The Brady Bunch sometimes sang songs, in an apparent effort to attract viewers of The Partridge Family, another family sitcom that was popular in the early 1970s. In 1972, Williams and the other child actors from The Brady Bunch appeared on a music album entitled, "The Kids From The Brady Bunch." The album's most popular song was, "It's a Sunshine Day."
Williams has also appeared in several made-for-television Brady Bunch movies, including The Brady Girls Get Married (1981), A Very Brady Christmas (1988), and The Brady Bunch Movie (1995). Each of the Brady Bunch movies has been universally derided as being pure crap.Williams was apparently a horndog in real life, as he tried to hook up with Florence Henderson, who played his mother on the show. In 1992, his autobiography, Growing Up Brady: I Was a Teenage Greg was published. In his book, he claimed to have gone on a date with Henderson and to have hooked up with his Brady Bunch sister, Maureen McCormick. (His romantic exploits appear to have been limited to women - I was unable to find any evidence that Williams ever tried to get with the openly gay Robert Reed, who played his father on the show and actually died from complications due to AIDS in 1992).
Williams also claimed to have been a heavy drug user and was supposedly high on pot during the filming of several episodes of the Brady Bunch. Williams' book was on the New York Times' Bestseller list for three months and was later adapted into the 2000 made-for-television movie, Growing Up Brady.
In 2002, Williams appeared on an episode of Celebrity Boxing on the FOX network. Williams fought Danny Bonaduce and basically got his ass handed to him. Although much taller and bigger than Bonaduce, he was pummeled, knocked down five times before the referee finally called the match during the second round.

Williams now operates a fan portal/blog entitled The Greg Brady Project. Williams also hosts "The Barry Williams Show" on Sundays through Fridays on Sirius Satellite Radio's "Totally '70s" channel.
Williams' star has faded dramatically since The Brady Bunch went off the air in 1974. Unable to deal with his loss of fame and decreased cash flow, Williams has basically whored himself out and will do practically anything for money. For this and the fact that he looks a good 15 years older than his biological age, there can be no doubt that Barry Williams is one washed up celebrity!