From collegiate walk-on to NFL superstar, Clay Matthews has come a long way. (Creative Commons)

Now, he has something his dad never got playing 19 seasons in the NFL: A Super Bowl ring.

You’d think Clay Matthews III grew up hopping and skipping around bronze busts, romping down Hall of Fame rows. His own gold blazer hanging in a closet somewhere, waiting since birth.

His pedigree reads like Man O’ War, like an Arabian horse sired over and over to complete perfection.

From all sides, his genetic code is stamped with footballs. His nickname is, in all seriousness, “Bloodline.”

Consider his genealogy —   

Father: played the third most games in NFL history. Uncle: Inducted into the Hall of Fame. Grandfather: Played for the 49ers. Brother: Linebacker at Oregon. Cousin: Starting center for the Titans.

Like the mob, he was born into this.

Clay Matthews III didn’t start for his high school football team up until his senior year.

For most sons whose daddy coaches, it’s the same story. They are, most always, quarterback. Every interception is the offensive line’s fault, or a bad break. It’s a lock, it’s expected -- a common complaint of prep athletes around the nation.

Matthews was undersized and, to be honest, not very good.

So as defensive coordinator, his coach, four-time NFL Pro Bowler Clay Matthews Sr., relegated him to the bench.

There was no recruiting Matthews III. He came to USC hoping to walk on.

This weekend, Matthews III became one of the NFL’s biggest stars. Moments after his coach told him to make a play, he speared Steelers’ running back Rashard Mendenhall with the force of a lifetime of frustration; better put, a Mack truck.

He lowered his head, and struck — not just Mendenhall, but the ball, jarring it loose and to the ground. The ensuing fumble recovery changed everything.

Three years after finally working his way to a starting position with USC, he is regarded as quite possibly the best defensive player in the NFL. He is now called a champion.

Four years ago, no one would have ever imagined that Clay Matthews III — a nice special teams contributor — would become the brightest shining star in a galaxy of talent.

In 2007, USC fielded one of the greatest defensive teams of all-time.

Matthews was lost among Brian Cushing, Rey Maualuga, Keith Rivers and Kaluka Maiava — each among the nation’s best linebackers.

All four are in the NFL. All four are wondering how the kid they knew as the back-up linebacker overtook them.

Here’s a look at all four, then and now:

THEN:

Keith Rivers was so highly touted when he entered USC, he was promised jersey No. 55, making him a part of the illustrious “Club 55” group that in the past included Junior Seau, Willie McGinest and Chris Claiborne.  He grabbed a starting linebacker position his sophomore season and held it until he was drafted. His junior year, he was All-Pac-10 first team and his senior year, an All-American.

He was the ninth overall pick in 2008.

Brian Cushing started ahead of Matthews for three seasons, and, in all, started all four years, including starts in four Rose Bowls. He was Defensive MVP of the 2007 Rose Bowl Game and earned All-American honors in 2008.

He was drafted 15th overall in the 2009 NFL Draft.

Rey Maualuga immediately made an impact, starting his freshman year, before becoming a three-time first-team All-Pac-10 selection, a consensus All-American and, like Cushing, a Rose Bowl MVP. He was drafted 38th.

Kaluka Maiava was the 2009 Rose Bowl Defensive MVP and was drafted in the fourth round of the 2009 draft.

NOW:

There have been disappointments, mediocrity and legal problems.

Cushing got off to a great start, one of three rookies to make the Pro Bowl his rookie season. He was also NFL Defensive Rookie of the Year.

This year, his bio got stamped with steroids. He was suspended for the first four games of the 2010 season and had a less-than-spectacular sophomore season.

Maualuga had a lackluster first year; then finished it injured.

Just after completing his second season, Maualuga also got into trouble. His DUI earned him seven days in jail, two years probation and a suspension on his driver’s license. His second season was typical.

Rivers got smacked in the jaw by Steelers wide receiver Hines Ward (who hasn’t Ward injured?) and missed the final nine weeks of his rookie season. In his second and third years, he accumulated 72 and 77 total tackles, respectively  — average numbers.

Maiava played in two games this season and made one tackle.

MATTHEWS THEN/NOW:

He has said he was 5-foot-5 entering high school and 170 pounds.

Now, he is 6-foot-3 and 255 pounds.

His rookie season he had 10 sacks. This year, 13.5, and he was in the mix for Defensive Player of the Year, losing out to another USC alum: Troy Polamalu.

He is a two-time Pro-Bowl selection and this year’s winner of the Professional Butkus Award, given to the NFL’s top linebacker.

He is one of the game’s greatest inspirations.

“I think you’re looking at a Hall of Fame kid,” his former head high school coach Charlie Wegher said.