According to ESPN.com's Jamison Hensley, Harbaugh said, "Everybody has these expectations that you're going to see fireworks. I thought he played well."
In Baltimore's 17-16 win over the Chicago Bears in the Hall of Fame Game, Jackson finished 4-of-10 passing for 33 yards, one touchdown and one interception. He also rushed for 25 yards on eight carries.
Jackson played the entire second half in Thursday's game.
The rookie first-round pick's best moment came when he threw a seven-yard touchdown pass to rookie tight end Hayden Hurst in the third quarter.
Jackson felt as though he left some plays on the field based on his comments after the game: "It wasn't what I expected. I felt like I should've had more touchdowns out there. There is still room for improvement for us."
While Harbaugh was happy with Jackson's showing, he acknowledged there is plenty of room for growth:
"The first task we gave him was to operate the offense. He did. He got the plays called. He got people lined up. He got snap counts off. That stuff gets taken for granted. Well, we say you got to go down the field and score points. And sure you do. But there's a rookie quarterback out there for the first time handling the whole offense. I thought he did a very good job. That's really what I asked him to do today. He'll build from that."
After Jackson enjoyed two highly productive seasons as the starter at Louisville, Baltimore traded back into the first round of the 2018 NFL draft to take him with the No. 32 overall pick.
Jackson won the Heisman Trophy at the conclusion of the 2016 season and followed that up with a total of 45 passing/rushing touchdowns last season.
Following Thursday's game, Jackson admitted that the speed in the NFL compared to college is at a different level: "You can't jog. The linemen are fast. The NFL speed is totally different from college."
The selection of Jackson may have been a sign that the Ravens believe time is running short on Joe Flacco as a quality starting NFL quarterback.
Regardless of the rationale behind the pick, the Ravens have the luxury of not having to press Jackson into action.
Along with Flacco, the Ravens have another veteran quarterback on the roster in Robert Griffin III. Because of that, Jackson can sit and learn rather than being thrown into the fire immediately.