He played college football for the Georgia Bulldogs,[4] where he kicked the longest field goal in Rose Bowl history.

[8][12] In the 2018 Rose Bowl, Blankenship made a record-long 55-yard field goal that proved pivotal in shifting the momentum away from Oklahoma, leading to Georgia's eventual 54–48 overtime victory.

[5][12] In the 2018 College Football Playoff National Championship game against Alabama, Blankenship hit a 51-yard field goal in overtime to put the Bulldogs temporarily ahead.

[11] By making 87 percent of his field goals attempts, Blankenship had the sixth-best season in school history.

[19] In December 2019, Blankenship won the Lou Groza Award, given to the nation's top placekicker.

[26][27] By the end of the regular season, Blankenship had converted 43 out of 45 extra point attempts and made 32 out of 37 field goal tries, with a long of 53 yards.

[29] During the 27–24 road loss to the Buffalo Bills in the Wild Card Round of the playoffs, Blankenship made one of his two field goal attempts and converted his only extra point opportunity.

[30] Blankenship played the first five games for the Colts before being placed on injured reserve on October 16, 2021, due to a hip injury.

[32] On September 11, in the Colts' season opener against the Houston Texans, Blankenship went 2-for-3 on field goals, kicking two kickoffs out of bounds and missing a potential game-winning 42-yarder in overtime as the game ended in a 20–20 tie.

[45] On January 8, 2025, Blankenship signed with the St. Louis Battlehawks of the United Football League (UFL).

[47] Ken coached the kickers on every team for which Rodrigo played from fifth grade through the end of high school.

A pet owner, Blankenship owns a cat named Lucas, which he has shown in interviews made at his home.

Blankenship looks up to Eric Dickerson and Kareem Abdul-Jabbar and is noted to wear glasses while playing.