"As I reflect on the journey till today I am reminded of the change that it reflects: that we are a community and a country that has continuously opened our hearts and changed our minds and increasingly judged people on their skills and talents not on their identities," McBride said.
McBride's swearing-in ceremony sheds light that while 4.5% of adults identify as LGBTQ in the US, according to the Victory Institute, less than 1% are elected officials.
"As I was growing up and I was struggling with who I am and how I fit into this world, I saw that in politics it was the place you could make the most amount of change for the most number of people in the most number of ways possible," McBride said.
WATCH: Meet the country's first openly transgender state senator
Meet the country's first openly transgender state senator
McBride defeated Republican Steve Washington in November to win the seat that became open following the retirement of the longest-serving legislator in Delaware history.
She won in a heavily Democratic district stretching from northern Wilmington to the Pennsylvania border.
McBride interned at the White House under former President Barack Obama and made history at the 2016 Democratic National Convention as the first openly transgender person to speak at a major party convention.
She succeeds fellow Democrat Harris McDowell, who had held the Senate seat since 1976 and endorsed McBride's candidacy.
McBride's campaign generated interest and money from around the country, generating more than $270,000 in donations as of early October, eclipsing fundraising totals even for candidates for statewide office in Delaware.
A former student body president at American University, McBride started in politics as a volunteer for Matt Denn, former legal counsel to Delaware's governor, during his successful 2004 campaign for insurance commissioner. Denn, who later served as lieutenant governor and attorney general, worked with McBride's father at a Wilmington law firm known for its close ties to the Democratic Party establishment.
Sarah McBride elected as country's first transgender state senator
McBride later worked on the campaigns of former Gov. Jack Markell and former state Attorney General Beau Biden.
She says she's ready to hit the ground running, representing the first district, the community which raised her. Her first order of business is tackling the COVID-19 crisis.
"All of us are incredibly eager to do the work necessary to help this state face the COVID-19 crisis, save as many lives as possible, reopen safely, get those vaccines out as efficiently and effectively as possible," she said.
McBride acknowledged in her speech why she purposely chose being in front of the Claymont Community Center. It was the former Claymont High School. She said in five years, she still hopes to represent the community that raised her and elected her.
The Associated Press contributed to this report.