Maxwell began 2017 with Nashville, and was recalled and optioned multiple times before he was called up to Oakland for the remainder of the season on June 22. In 76 games for Oakland, he batted.237 with three home runs and 22 RBIs. On September 23, 2017, Maxwell became the first MLB player to join other US athletes protesting racial injustice by kneeling during the national anthem; Maxwell placed his hand over his heart, and teammate Mark Canha stood next to Maxwell and put a hand on his shoulder in support. Maxwell's actions came in response to President Donald Trump's comments that professional football franchise owners should fire players who knelt during the anthem. On Twitter and through his agent, Maxwell said his decision to kneel represented concern for racial injustice as well as freedom of speech and exercise of peaceful protest. The Oakland Athletics immediately issued a statement saying the team "pride ourselves on being inclusive" and supports "players' constitutional rights and freedom of expression." While supported by the A's, Maxwell's future career in the MLB was seen as impacted by the reaction to his kneeling. He remained the only MLB player to protest by kneeling until 2020, when the league allowed for "Black Lives Matter" patches and organized league-wide kneeling for social justice in the aftermath of the nationwide protests of the death of George Floyd by police in Minneapolis. Subsequently, Maxwell said that while eating at a restaurant with a city councilman with whom he had attended high school, Devyn Keith, and another friend in Maxwell's hometown of Huntsville, Alabama, a waiter objected to Maxwell's protest and refused to serve their table. The waiter denied the story, saying he did not know who Maxwell was.
2018
Maxwell began 2018 with Oakland. He was placed on the restricted list on May 16 when the Athletics entered Canada to play the Toronto Blue Jays, as he was not eligible for entry into Canada as he had not yet been sentenced for his assault with a deadly weapon charge that was placed in the previous off-season. He was designated for assignment on September 1, 2018. For the season with the A’s, he batted.182/.207/.309 with one home run. He elected free agency on November 2, 2018.
Acereros de Monclova
2019
On March 6, 2019, Maxwell signed with the Acereros de Monclova of the Mexican League. He was successful in his first season with the club, slashing.325/.407/.559 with 24 home runs and 112 RBIs across 109 games played. Maxwell was also selected to the LMB All-Star Game and won the Serie del Rey with the Acereros, which was the first-ever championship for the team.
On July 27th, 2020, the New York Mets signed him to a minor-league deal, pending physical and a negative COVID-19 test.
Personal life
On October 28, 2017, Maxwell was accused of pointing a firearm at the head of a female food delivery driver delivering food to him at his home in Scottsdale, Arizona. Maxwell was arrested on a felony charge of aggravated assault with a deadly weapon. On July 2, 2018, he was sentenced to two years probation for disorderly conduct.