Among Baldwin's best lines from the sketch:
"Some people have called me a serial tapist - when you're President they let you do that."
"I sit on every chair like it's a toilet."
"Nothing's going to stop me because I have the Republicans in the palm of my hand."
Referring to his presidency as a TV show, he vowed it will run for eight years.
"In an upcoming episode we will find out that Kellyanne (Conway) has been dead this whole time."
When pressed by Holt about his choice to replace Comey, 'Trump' vowed that it will be someone "so bonkers you're going to wish like hell it was Judge Judy".
Later in the show, Melissa McCarthy made a triumphant return as Sean Spicer in a long sketch that had him battling for his job after Sarah Huckabee Sanders began filling in this week.
The segment began with McCarthy-as-Spicer hiding in the bushes outside the window, with Sanders (Aidy Bryant) filling in at the podium, and the press corps begging her to stay on. "Can't you just do this full-time instead of him?" they pleaded.
But McCarthy's Spicer returned to the lectern, armed with a fire extinguisher to put "his pants out" for lying.
"Spicey's back, Sarah's out," announced McCarthy as he sprayed the extinguisher's white foam at reporters.
McCarthy swatted away questions from the reporters questioning Trump's fitness. "If he's crazy, he's crazy like a fox with mental problems," Spicer said.
Asked about Trump's connections to Russia, McCarthy-as-Spicer responded: "Let me just put this whole Russia thing to bed. Trump is innocent. How do we know? Because he told us so. They're going to prove it with a certified letter."
Spicer then read off the tracking numbers - only then to realize it was his own bank routing number. "No one use it," Spicer declared.
McCarthy then brought a set of Russian nesting dolls to illustrate the relationship between Trump and Comey, ultimately explaining that Comey's firing was due to "Trump's good friend" Jeff Sessions, illustrated by Pikachu.
When asked: "Where you surprised Trump fired James Comey instead of you" McCarthy as Spicer ripped a beam off the wall and threw into the press corps.
"I hope to god it killed her."
Pressed on if Trump is lying to him, Spicer insists "he wouldn't do that, he's my friend."
Spicer then left the press briefing room on his motorised podium, driving through the streets of Manhattan in search of Trump.
"I promise I'll talk better," he yelled while rolling down 58th Street.
Spicer arrived at Trump Tower, only to be told by the doormen that Trump doesn't come there anymore. He finally finds Baldwin-as-Trump at a golf course in New York, and asks him the burning question: "Have you ever told me to say things that aren't true?"
Replies Trump, "Only since you started working here."
Trump reassures Spicer that he won't replace him with Sanders ("She doesn't have your special spice").