High Noon makes programmes such as Cake Boss - a behind-the-scenes look at a New Jersey bakery - and Tough Love - a dating "bootcamp" show.
The company, founded in 1997 by TV executive Jim Berger, now supplies 18 US cable networks. ITV is buying a 60% stake for its initial 25.65 million US dollar outlay, with a top-up payment due in 2015 based on the performance of the company, and an option to buy the remainder of the business later.
High Noon made a profit of 5.7 million US dollars (£3.7 million) in 2012.
ITV's acquisition follows its £18 million deal last month to buy London-based producer The Garden, maker of fly-on-the-wall documentaries such as 24 Hours In A&E and Inside Claridge's.
In December it bought a controlling stake in Los Angeles-based reality TV firm Gurney Productions for 40 million US dollars (£24.7 million).
ITV chief executive Adam Crozier said: "A key part of our transformation plan is to create a strong international content business and this is a further significant step forward in achieving that goal.
A spokesman said programmes produced by High Noon would not necessarily be shown on the ITV network and the purpose of the acquisition was "bolstering our own production business".
ITV has been boosting its studio arm with original content it can sell around the globe, helping it offset a stagnant advertising market. The division grew revenues by £100 million to £712 million last year following the success of programmes such as Titanic and Vera for ITV and Shetland for the BBC.