Though his role was to speak on the president's behalf, Spicer often made headlines for his own words when he made missteps, and for the absence of words -- regularly conceding that he did not know the answers to reporters' questions or that he would "get back" to them.
The press secretary's resignation came the same day that financier Anthony Scaramucci accepted an offer to replace Dubke.
Here's a look at some of the notable moments featuring Spicer since Trump's inauguration:
Inauguration crowd size
In his first opportunity to address the media, the day following Trump's inauguration, Spicer unleashed a blistering attack on the press' portrayal of the size of the crowd on the National Mall at the event.
Spicer lambasted news organizations for using images "intentionally framed" to diminish the size of the audience and made several factually incorrect statements about the use of coverings on the grass at the Mall during President Barack Obama's first inauguration and metro ridership numbers from the Washington Metropolitan Area Transit Authority after reports the day prior noted attendance appeared down from 2008.
After not taking questions while giving the statement, Spicer answered for his comments two days later, responding to inquiries about the information he provided by saying, "Sometimes we can disagree with the facts but our intention is never to lie."
'It's not a travel ban'
"Well, first of all, it’s not a travel ban," said Spicer, who attempted to make a point about the word "ban" only applying to an order that completely halts something, rather than merely limiting it, as the president's action did.
However, Trump himself called the order a "ban" a day earlier in a tweet referring to the executive order. After Spicer again protested the word's inclusion in a question from Yahoo News' Hunter Walker, NBC News' Kristen Welker called attention to the language in the president's own tweet.
"He says it's a 'ban,'" said Welker, to which Spicer claimed that Trump was only using the word because the media was using it.
"I think that the words that are being used to describe it are derived from what the media is calling this," said Spicer.
In lieu of a formal press briefing on Feb. 24, Spicer instead decided to hold an informal gathering with reporters known as a gaggle, and took the additional step of only inviting certain news outlets.
Those left out included the New York Times, Los Angeles Times, Politico and CNN. After learning those organizations would not have a representative, journalists from The Associated Press and Time magazine boycotted the conversation.
Spicer defended himself by saying the gaggle was originally supposed to be comprised of a smaller group and he simply chose to expand it, but the White House Correspondents' Association, which represents the press corps, cried foul, saying they disapproved of the way the situation was handled.
'Stop shaking your head'
Throughout his tenure, Spicer, who has been lampooned as a kindergarten teacher on "The Daily Show," often chided reporters for talking over one another and dismissively referred to questions as "cute." He took his actions a step further on March 28 when he chastised American Urban Radio Networks' Ryan for her body language.
As Ryan posed a question about the number of impediments the administration was encountering in its first months, Spicer cut her off, accused her of harboring an agenda and encouraged her to "report the facts." During his response, he also noted that she was shaking her head.
The pair continued their exchange, but shortly after, Spicer again took note of Ryan's movements.
"Please stop shaking your head again," said Spicer.
After the briefing, Ryan expressed her frustration with a tweet, writing, "Lawd!!!!" At the next day's news conference, in what appeared to be an act of goodwill, Spicer called on Ryan first.
In April, Spicer addressed the U.S. airstrikes in Syria, launched in response to a chemical attack in that country that was blamed on its government.
Seemingly attempting to justify Trump's order of the missile launch, Spicer compared the cruelty of the Syrian chemical attack to the actions of Hitler during World War II.
"You had ... someone as despicable as Hitler, who didn't even sink to using chemical weapons," said Spicer, neglecting the millions killed in the gas chambers of Nazi concentration and extermination camps. He further referred to the camps as "Holocaust centers."
Facing nearly universal scorn for the remarks, Spicer eventually apologized, telling CNN, "It was insensitive and inappropriate" and that he "shouldn't have done it."
'He gets beat up'
Commenting publicly about the difficulties faced by his press secretary, Trump defended Spicer and principal deputy press secretary Sarah Huckabee Sanders during a Fox News interview in which he also threatened to cancel "all future press briefings."
"You have a level of hostility that’s incredible and it's very unfair," said Trump. "Sarah Huckabee is a lovely young woman. You know Sean Spicer. He’s a wonderful human being. He’s a nice man."
Trump wouldn't go so far as to say Spicer should be replaced when prompted by interviewer Jeanine Pirro, but conceded that the aide faced his share of difficulties.
"He’s doing a good job, but he gets beat up," said Trump.
Just after midnight on May 31, Trump sent a tweet that read: "Despite the constant negative press covfefe." The apparent misspelling of the word "coverage" quickly became a meme as social media users joked about covfefe's meaning and why the president published the incomplete post.
After an unusually long amount of time for a post containing an error -- a fact that fed the newfound meme -- the post was deleted and Trump himself joined in on the humor.
"Who can figure out the true meaning of 'covfefe' ??? Enjoy!" he wrote later that day.
When asked about the missive, Spicer responded: "The president and a small group of people know exactly what he meant." Many were left wondering whether he was serious or making a joke.
Rumors about his role
After Dubke resigned in June, rumors swirled that Spicer could relinquish his public role as press secretary to focus on communications in a behind-the-scenes capacity. Spicer held the communications director title at the start of Trump's presidency before Dubke took the job in March.
Spicer addressed the growing reports after he was asked about them at the June 20 briefing and whether he could share any changes to the communications team.
"I’m right here," said Spicer on June 20, adding, "We’re always looking for ways to do a better job of articulating the president’s message and his agenda, and we’ll continue to have those discussions internally. When we have an announcement of a personnel nature we’ll let you know. When we have an announcement of a personnel nature we’ll let you know."