Merlini worked for Premcor Ltee, a commercial printing company in Saint-Lambert as a clerk, a board member and the vice-president (production sector) for 26 years.
Merlini was also a candidate in Saint-Lambert in the 1990 municipal elections and in La Prairie in 2003.
He was also involved with the Montreal South Shore Chamber of Commerce and the business association of La Prairie.
He also coached a local soccer team in La Prairie since 2001.
Until 2003, he was a Liberal supporter.
In 2006, he was named the vice-president of the ADQ.
Merlini was first elected in the 2007 election with 39% of the vote.