His mother, Aida, became the breadwinner.
"He passed away when I was 7, so my mother had to go to work," said Johnson, 26.
"She worked while getting her nursing license, and I saw how hard she worked. That's how I knew we had to get by, through her approach. She could have sat around and grieved, but she knew she had a family to feed. I learned a lot of lessons from her."
Johnson, an outside linebacker, is a nonstop motor player on the Ravens' defense, like tackle Kelly Gregg and middle linebacker Ray Lewis. They know only one speed -- fast -- even in practice.
Johnson, though, has been even faster on game day. He is second on the team in tackles with 16, behind Lewis' 25.
That's impressive because, in the Ravens' scheme, Lewis should always be first in tackles, followed by either the strong safety or the weakside linebacker.
Johnson is making this impact in his first season as a starter, replacing Pro Bowl outside linebacker Adalius Thom- as, now with the New England Patriots. Johnson won't make anyone forget Thomas, but a lot of people now want to know who Johnson is.
"I have nothing to prove to anybody but my teammates and what they uphold and expect as a defense," Johnson said. "They have trust in me, and we play as a group. I don't feel any pressure. My goal was just to improve from the beginning of training camp till now, and I have taken small steps each week to get better."
Johnson has been a force. Teams have tried to run at him with little success, and they have had just as much of a problem running to the opposite side of the field. Despite weighing 270 pounds, Johnson has chased down running backs several times and is relentless in pursuit.
That's surprising to some, but not to the Ravens. They drafted Johnson in the fourth round in 2003 because of his speed and desire. At Alabama, Johnson was a defensive tackle, but he was too small to play that position in the NFL.
He was a tweener during his first couple of seasons in Baltimore, playing end and linebacker.
After Thomas left as a free agent, the Ravens re-signed Johnson to a five-year deal in March, assuming he would have to go through some on-the-job training. That must have taken place in training camp or during the preseason.
In the season's first two games, Johnson has been flying to the ball, playing on the same level as Bart Scott, Terrell Suggs and Lewis.
"Coach Fitz [linebackers coach Jeff FitzGerald] has helped me a bunch in fine detail," Johnson said. "He has taken a lot of time with me, and I need those things, the finer points. Some of the guys who have been around longer don't need it, but I need the smaller steps, and obviously Rex [defensive coordinator Rex Ryan] and Ray have been a big help."
Ryan was smart enough to not try turning Johnson into another Thomas. On running situations, Johnson plays the strong side as Thomas used to do. But on passing situations, Scott plays the multi-faceted roles left vacated by Thomas. "I'm jumping into coverage a lot," Johnson said. "That's what the position entailed, a lot of dropping, and I understood that. I had a good understanding of the zone coverages we run, and I could see the pass combinations and routes really well. But the man-to-man stuff is what I needed to work on, and it's gotten better."
Ravens general manager Ozzie Newsome likes the pace of the transition. An alumnus of Alabama, he got the inside skinny on Johnson.
Johnson is a good old country boy who resides in Tuscaloosa, Ala.
He likes Pearl Jam but loves Lynyrd Skynyrd. He prefers to be outdoors hunting deer, turkey or ducks. But the only thing he likes more than hunting is football. And he likes to practice and work.
"He didn't want to become the weak link of the defense, where there were 10 players and Jarret Johnson," Newsome said. "He has survived on quickness and an understanding of the game. Do you realize that he was the only two-time captain in the history of Alabama? That says something."
It speaks volumes about his work ethic.
"I think about him a lot," Johnson said of his father. "I think his death and the way my mother handled it helps me through tough situations more than I realize. I think he would be pretty proud of me."