Grosjean, from France, was unveiled at a news conference held at the team's base in Kannapolis, North Carolina, on Tuesday.
He has 78 grand prixs under his belt, along with 10 podium finishes, and will make the move from Lotus at the end of the 2015 campaign.
The 29-year-old is in his third year at Lotus, having spent one year driving for the team under its guise as Renault in 2009.
He will link up with the Haas F1 team which is the brainchild of Gene Haas, co-owner of Stewart-Haas Racing in the NASCAR Sprint Cup Series.
"What Gene Haas and everyone at Haas F1 Team is building is impressive, and I'm very proud to be a part of it," Grosjean said.
"Formula One is incredibly competitive and the only way to succeed is by finding new ways of doing things.
"This is a new opportunity with a new team that is taking a very different approach to Formula One. I believe in their approach and they believe in me.
"While I am committed to giving my absolute best to my current team in these last five races, I am very excited for what the future holds at Haas F1 Team."
Haas has already tasted success in the premier U.S. racing series when the Stewart-Haas Team, which he founded with three-time Sprint Cup champion driver Tony Stewart, won the 2011 Sprint Cup Series championship.
F1 last expanded the grid in 2010 when three new teams joined. Of the trio, two are still racing in their current guises -- Caterham and Marussia.
"We wanted an experienced driver capable of developing our car and our race team into one that can score points and better itself each race and each season. We found him in Romain Grosjean," said Haas.
"I've been involved in motorsport for a long time and learned early on the most crucial component is the driver. Romain has strong credentials and he will be an important asset to Haas F1 Team."
The last U.S. backed team ran a limited number of races during the 1985 and 1986 seasons under the Lola-Hart moniker.
Other American teams to enter the sport include Eagle, which debuted in 1966, as well as Shadow and Penkse, both of which raced in the 1970s.
The USF1 team launched an unsuccessful bid to join F1 for the 2010 season after difficulties securing financial backing.