Born in Rouyn, Quebec Bob Blackburn played his junior hockey with the Barrie Flyers of the OHA in the late 1950s. He turned pro with the Quebec Aces of the QHL in 1958-59 playing alongside the likes of Skip Teal and Joe Crozier.
The bulk of Blackburn's career was spent in Providence with the AHL's Reds from 1960 to 1966 where he provided a steadying influence on defense. He also made brief stops in Vancouver of the WHL and Buffalo of the AHL where he won the Eddie Shore Award for the league's top defenseman.
Blackburn broke into the NHL as a 30-year-old rookie with the New York Rangers in 1968-69, suiting up for eleven games with the club. In the summer of 1969 he was claimed by the Pittsburgh Penguins and played in 60 games. In 1970-71 he was in the lineup for 64 games. In 135 NHL games Blackburn had eight goals and 20 points. He played one more year of pro hockey in 1971-72 with Rochester of the AHL before retiring at the age of 34.