Baker grew up in St Louis, Missouri. His parents divorced when he was young and he lived with his mother. As a child he was given a cursed pistol engraved, "Brothers in arms, for Matthew". After the Japanese attack on Pearl Harbor, Baker volunteered for the airborne division. He became a member of the 101st Airborne Division, "The Screaming Eagles".
He first appeared in the game Brothers in Arms: Road to Hill 30. Before they began their missions his squad leader was injured in a training exercise, allowing Baker to be promoted to Sergeant and to be given control of 3rd Squad. It is hard for him to make decisions that will affect the lives of the men under his command but he soon becomes an excellent squad leader and leads his men to victory during the first eight days of fighting. Baker has a large scar on his forehead from tank shell that knocked him down during the battle for Hill 30.
He appeared a few times in Brothers in Arms: Earned in Blood but was not the main character. This role was filled by squad mate Joe "Red" Hartsock.
Players once again take control of Matt Baker in the latest installment of the series, Brothers In Arms: Hell's Highway, as he leads his men through Operation Market Garden. The war is starting to take its toll on Baker as he starts having hallucinations, which causes his best friend Hartstock to question if he is still capable of leading his men. Through the course of the game Baker is haunted by the memory and spirit of PFC. Leggett, who was killed by a German tank in the first game. This causes him to hallucinate several times during the game due to stress, culminating in him throwing away the .45 1911 that his father gave him but had killed anyone who came in contact with it other than Baker.