Krishnamoorthi, 43, won the Chicago-area US House of Representatives seat, the 8th Congressional District, vacated by Tammy Duckworth who won Illinois's US Senate seat.
New Delhi-born Krishnamoorthi, a laboratory executive, has parental roots in Chennai. He was endorsed by US President Barack Obama.
"Thank you! I'm honoured and humbled to be the next Congressman of Illinois's 8th District! #IL08," Krishnamoorthi said in a tweet, and thanked supporters in his victory speech.
He is the second Hindu-American to be elected to the US House of Representatives, after Tulsi Gabbard, who is seeking her third term in US Congress from Hawaii.
Krishnamoorthi and DiCianni were vying to win the seat vacated by Tammy Duckworth who won Illinois's US Senate seat.
Krishnamoorthi had received 81,263 votes against his rival’s 54,149 votes when almost 80 per cent of the votes were counted for the eighth Congressional district of Illinois.
Successful in his second attempt, Krishnamoorthi is only the second India-born member of the Congress after Dalip Singh Soundh in 1950.
The two other Indian-Americans elected to the House of Representatives -- Bobby Jindal and Dr Ami Bera -- were born in the US. Bera is seeking his third consecutive term from California.
Krishnamoorthi, who previously was the policy director and a senior advisor for Barack Obama's 2004 US Senate campaign, and served as an advisor to Obama's 2008, served as deputy treasurer of Illinois from 2007-09 under Illinois Treasurer
Alexi Giannoulias, and in 2010 ran for the Democratic nomination for Illinois State Comptroller, losing to David E Miller by less than one per cent of the vote.
Born in New Delhi on July 19, 1973, his parents immigrated to Buffalo, New York, when he was three months old.
Krishnamurthi currently serves as president of Sivananthan Labs and Episolar, Inc, small businesses that develop and sell products in the national security and renewable energy industries.
He is a co-founder of InSPIRE, a non-profit organisation that provides training to Illinois students and veterans in solar technology, and was formerly vice chairman of the Illinois Innovation Council, whose mission is to promote innovative technologies that support economic growth and job creation in Illinois.
The eighth congressional district has quite a lot Asian-Americans along with a sizeable Indian-American population.
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