In 2012, Amanda Giroux competed in the Miss Ohio Teen USA 2013 pageant and placed as a semi-finalist in the competition. Encouraged by her success, she return to the Miss Ohio Teen USA stage in 2013 to compete for Miss Ohio Teen USA 2014. This time she placed 1st Runner-up. Once again determined to take home the crown, Giroux returned to compete in 2014 for the Miss Ohio Teen USA 2015 pageant, where she placed as 1st Runner-up once again.
In 2015, Giroux represented Delaware at the Miss Collegiate America 2015 pageant. She ultimately placed 2nd Runner-up in the competition.
In 2016, she competed for the title of Miss Ohio USA 2017 and placed as a semi-finalist. In 2019, Giroux competed with 21 contestants for the title of Miss Utah USA 2019 and was crowned by Narine Ishhanov at the Kingsbury Hall in Salt Lake City on Saturday, January 26, 2019. She represented the Riverdale area at the state pageant, and will go on to compete for the title of Miss USA 2019.