He was nicknamed "Rocky" as a baby. Bleier said, "As the first born of the family, my dad was proud, as all parents are. And the guys would come into the bar and say 'Bob, how's that new kid of yours?' And my dad would go, 'Aw, you should see him, guys, looks like a little rock sitting in that crib. He's got all these muscles.' So they'd come back in the bar and they'd say, 'Hey Bob, how's that little rock of yours?' So after that, that's how I got it. It stuck."
Bleier graduated from Xavier High School in Appleton, Wisconsin, in 1964. While in high school, Bleier starred in football and basketball. In football, he was a three-time all-state selection as running back and won all-conference honors at both linebacker and defensive back.
After his 1968 rookie season with the Pittsburgh Steelers, Bleier was drafted into the U.S. Army in December 1968 during the Vietnam War. He volunteered for duty in the South Vietnam and shipped out for Vietnam in May 1969 assigned to Company C, 4th Battalion (Light), 31st Infantry 196th Light Infantry Brigade and assigned as a squad grenadier operating a 40mm M79 grenade launcher. On August 20, while on patrol in Heip Duc, Bleier was wounded in the left thigh by an enemy rifle bullet when his platoon was ambushed in a rice paddy. While he was down, an enemy grenade landed nearby after bouncing off a fellow soldier, sending shrapnel into his lower right leg. He lost part of his right foot in the blast as well. He was later awarded the Bronze Star and Purple Heart. His rank was Specialist 4.
While he was recovering in a hospital in Tokyo, doctors told him that he would not play football again. Soon after, he received a postcard from Steelers owner Art Rooney which just read "Rock - the team's not doing well. We need you. Art Rooney". Bleier later said, "When you have somebody take the time and interest to send you a postcard, something that they didn't have to do, you have a special place for those kind of people".
Bleier rejoined the Steelers in 1971. Upon his return, he couldn't walk without being in pain, and weighed only 180 pounds (82 kg). He spent two years trying to regain a spot on the active roster, and was waived on two occasions. But Bleier never gave up, and said that he worked hard so that "some time in the future you didn't have to ask yourself 'what if?'". An offseason training regimen brought Bleier back to 212 pounds in the summer of 1974, and he earned a spot in the Steelers' starting lineup.
Since Preston Pearson was wearing number 26 (the number Bleier wore his rookie season before he went to Vietnam), Bleier switched to number 20 when he returned to the team. After Pearson was traded to the Dallas Cowboys in 1975, Bleier kept the number 20, with which he had become associated.
In addition to being a great lead blocker, Bleier was the second of the Steelers' rushing weapons (Franco Harris was the primary back), but was effective nonetheless at both blocking and rushing. In 1976, both Harris and Bleier rushed for over 1,000 yards, making this the second NFL team to accomplish this feat, after Mercury Morris and Larry Csonka of the 1972 Miami Dolphins.
Bleier played in the first four Steeler Super Bowl victories, and caught the touchdown pass from Terry Bradshaw that gave Pittsburgh a lead it would never surrender in Super Bowl XIII. He also recovered Dallas's onside kick in the closing seconds, sealing the Steelers' victory.
Bleier retired after the 1980 season with 3,865 rushing yards, 136 receptions for 1,294 yards, and 25 touchdowns. At the time of his retirement, he was the Steelers' fourth all-time leading rusher.
Bleier has four children. He has two children from his marriage with Aleta Giacobine Whitaker, from whom he was divorced in October 1996. He also has two adopted children with his second wife, Jan Gyurina. As of 2011, he lived in Mt. Lebanon, Pennsylvania.
Bleier has become an author and speaker on retirement and financial management. He has authored the book Don't fumble your retirement and is the co-host of a weekly radio show The Rock on Retirement on Pittsburgh radio station 104.7 FM WPGB. He runs Bleier Zagula Financial with his business partner Matt Zagula.
The football stadium at Xavier High School was renamed Rocky Bleier Field on the Knights of Columbus Sports Complex. on October 12, 2007. Bleier tossed the coin to start the high school football game that day. He had spoken earlier in the day to students at an assembly. The entire student body wore T-shirts with his number 23, the only number retired in the school's history. On the following day, the third day of a three-day event, mayor Tim Hanna unveiled a street named in his honor. The former Oneida Court was renamed Rocky Bleier Run.