Welcome back, Alex!
In his customary style, he succinctly summed up his return before getting right to the game.
"Today, 'Jeopardy!' begins its 36th season on the air, and I'm happy to report I'm still here,'' he said on the show.
It was the latest bit of good news for the "Jeopardy!" fixture, who announced in a video in August that his chemotherapy treatments had concluded and he was back to work.
"I've gone through a lot of chemotherapy and thankfully, that is now over," he said at the time. "I'm on the mend, and that's all I can hope for right now."
On social media, "Jeopardy!" fans and former contestants expressed their excitement at seeing Trebek's return on Monday night.
Trebek, 79, remained upbeat when first telling fans about his diagnosis in March.
"Now normally, the prognosis for this is not very encouraging, but I’m going to fight this, and I’m going to keep working," he said at the time. "And with the love and support of my family and friends and with the help of your prayers also, I plan to beat the low survival rate statistics for this disease."
Trebek, who started taping the new season in July, also revealed to People magazine in May that some of his tumors had already shrunk by 50%.
"It helps all of us learn that working through cancer is possible, that you can continue to be that contributing member of your team, of your workplace, in Alex Trebek's case, this public figure on our televisions every evening that cancer didn't change that or diminish that it was just something that he had to go through," Rebecca V. Nellis, executive director of Cancer and Careers, said on TODAY Tuesday.