"A permanent replacement will be nominated at a later date", Trumptweeted.
Several hours after announcing the new AG via Twitter, Mr Trump was once again condemning the Mueller investigation.
Matthew Whitaker will take over as acting attorney general, the President said.
Mr Sessions cited his role as a senior adviser to the Trump presidential campaign as the reason he would not oversee the probe and instead and appointed Deputy Attorney General Rod Rosenstein to oversee the investigation.
Sessions' tenure as attorney general was often turbulent, and rumors indicated he might resign or be fired after the midterm elections.
US Attorney-General Jeff Sessions has resigned as the country's chief law enforcement officer at President Donald Trump's request.
Mr Sessions was the first USA senator to endorse Mr Trump for president.
He is reported to have frequented the Oval Office in the last few years and have an "easy chemistry" with Trump, serving as a "balm" in the tenuous relationship between Trump and Sessions that has finally come to a close.
Catherine Herridge reads Sessions's letter of resignation.
"Mueller has come up to a red line in the Russian Federation 2016 election-meddling investigation that he is dangerously close to crossing", wrote Whitaker in August of 2017.
Sessions announced his resignation in a letter to President Donald Trump. Appearing on CNN in July 2017, Whitaker once floated the idea that Trump could impede Mueller without firing him by simply allowing the attorney general to defund his operation.
Schumer says he finds the timing of Sessions' departure "very suspect".
Whitaker added in the piece that "it is time for [Rod] Rosenstein...to order Mueller to limit the scope of his investigation".
Sessions' ousting will likely tarnish the integrity of the ongoing Mueller investigation in the eyes of many Democrats and Republicans alike, and Whitaker can even technically fire the special counsel if there is "cause."
Trump's first attorney general aggressively denied any involvement that day to collude with Russian officials to interfere in the 2016 president election on Trump's behalf.
Breaking Bad movie is officially in the works
Production for the film is expected to begin mid-November at New Mexico . "Peter [Gould] wants it, the writers do, the actors do". Variety reports the two-hour film, now called Greenbriar , will begin filming this month .
Celebrities Who Suffer With Chronic Diseases
Now if that isn’t the epitome of what a BFF is, I don’t know what is! Selena continues to be on chronic medication. There is also a huge list of celebrities past like famous painter vincent Van Gogh who suffered with this disease.