Known for his ability to turn defense into offense and his effectiveness in various roles, Lumumba was a trailblazer in the Australian Football League as its inaugural Multicultural Ambassador and the first and only player of Brazilian and Congolese descent.

[5][6] In 2014, Lumumba was traded to the Melbourne Football Club, where he made an immediate impact on the team and continued in a leadership role[7] until his retirement in 2016, due to a concussion.

[8] In addition to his distinguished on field career, Lumumba played a significant role in promoting human rights and community engagement.

In 2006 he showed more improvement and was elevated to the senior list again during the year, this time due to the absence of Sean Rusling, playing a total of nine games.

Coach Mick Malthouse at one point in an interview challenged the AFL's rules on rookies in response to not being able to permanently play Lumumba in the seniors on the basis of his excellent form.

He was instrumental in Collingwood's 2010 grand final replay win over St Kilda and kicked a long goal from the boundary line late in the game.

He called the culture at Collingwood a "boys' club for racist and sexist jokes"[24] and stated that his teammates nicknamed him "chimp", a term with a strong history of connotations as a racial slur against black people.

He said that Collingwood coach, Nathan Buckley, told him to back off his accusations because it would throw the club president, Eddie McGuire, "under the bus".

A former executive producer at Network 10 stated, "What 'The Project' should do right now is show a bit of that clip, have Waleed and Pete sit there and talk about it and the lessons they've learned and what they'll do going forward.

"[36] Lumumba was born to an Afro-Brazilian mother and a Congolese-Angolan father in Rio de Janeiro, and moved to Perth, Western Australia when he was 3 years old.

[39] Lumumba's younger sister, Raquel O’Brien, is a podcast producer who has spoken publicly about her traumatic childhood.

[47] Team Individual Lumumba published a book in 2014 called It's Cool to be Conscious, that includes personal stories from his life, both on and off the field.