"Today, with incredible grief of our loss yet deep gratitude for the life she shared with us, we announced the passing of United States Representative Sheila Jackson Lee of the 18th Congressional District of Texas," Jackson Lee's family wrote. "A fierce champion of the people, she was affectionately and simply known as 'Congresswoman' by her constituents in recognition of her near-ubiquitous presence and service to their daily lives for more than 30 years."
Jackson Lee is the mother of Jason Lee, senior advisor to Chicago Mayor Brandon Johnson.
"Rep. Sheila Jackson Lee was a trailblazer in the truest sense of the word," Mayor Johnson said in a statement. "She defined her career through her advocacy, fighting relentlessly to create a better future for all, and her passing is a tremendous loss for residents of Texas' 18th Congressional District and our entire country. The First Lady, myself and my entire administration are sending our love and our deepest condolences to my senior advisor, Jason Lee, and Rep. Jackson Lee's family and loved ones during this difficult time."
The lawmaker's family said funeral arrangements are pending.
Early last month, Jackson Lee revealed she was diagnosed with pancreatic cancer and undergoing treatment, adding that she would be occasionally absent from her Congressional duties.
"I am confident that my doctors have developed the best possible plan to target my specific diseases. The road ahead will not be easy, but I stand in faith that God will strengthen me," Jackson Lee said in a statement on June 2.
A prayer and praise vigil was held shortly after in support of her fight. Jackson Lee's family or office didn't disclose whether her cancer was the cause of her death.
The Democrat's office boasted her accomplishments since she won her seat in 1994, crediting her with establishing the Juneteenth Federal Holiday and reauthorizing the Violence Against Women Act.
"However, she impacted us most as our beloved wife, sister, mother, and Bebe (grandmother)," Jackson Lee's representatives said.
Jackson Lee is survived by her husband Elwyn Lee and their two children.
Working in her last days
Just a week prior, Jackson Lee advocated on behalf of CenterPoint Energy customers by calling on the U.S. Department of Justice to investigate the utility company's response to Hurricane Beryl.
Jackson Lee was also months away from going for her 16th term in the U.S. House of Representatives after winning her Democratic primary.
The lawmaker fell last fall in her attempt to become the next Houston mayor in a close race against winner John Whitmire.