Addressing the news upfront, the host explained all of last week's tapings had been canceled so he could be with family following the devastating loss.
While holding back tears, Jimmy paid tribute to Gloria who he called "the best audience".
Fallon told a story Monday night about how his mother would hold his hand as a kid, and would squeeze three times and tell him that she loved him.
Fallon added that he's grateful that he can do "The Tonight Show" every night and thanked everyone for the support he received over the last week.
He continued by thanking his fans for all their support during the tough time, and said everyone at the show would "work really hard to bring some light and some laughter into the world".
Fallon ended his opening segment with a message for his late mother. "Look what you made me do", Jimmy teased in the clip.
Jimmy will be having his first new show following a week-long hiatus after the death of his mother earlier this month. Jimmy was at his mother's bedside, along with her loved ones, when she passed away at NYU Langone Medical Center in NYC.