Fred Guttenberg, whose 14-year-old daughter Jaime was shot and killed when a gunman began firing at students at Marjory Stoneman Douglas High School last week, confronted the senator during a live town hall aired on CNN.
"When I like you, you know it. When I'm pissed at you, you know it. Your comments this week and those of our president have been pathetically weak," Mr Guttenberg told Mr Rubio at the town hall in Florida.
"So you and I are now eye to eye. Because I want to like you, look at me and tell me guns were the fator in the hunting of our kids in this school this week," Mr Guttenberg continued. "And look at me and tell me you accept it and you will work with us to do something about guns."
Mr Rubio offered to explain his statements in response, but was cut off by boos from the crowd. At one point, CNN anchor Jake Tapper, who was moderating the event, had to step in and ask for respect for the senator in the interest of time.
"I'm saying that the problems that we're facing here today cannot be solved by gun laws alone, and I"m going to tell you what we've done already, and what i hope we'll do moving forward," Mr Rubio said.
Mr Guttenberg pressed him on whether guns were a primary factor in the shooting: "It's the weapon of choice, can you say that?"
"Absolutely," Mr Rubio said.
Mr Rubio said that he does not agree that an assault weapons ban should be put back in place at the federal level, saying that the laws do not actually ban all assault-style weapons.
Mr Rubio said that he is working on legislation to set a minimum age for gun purchases, improved background checks, and says he supports banning bump stocks.
The Florida senator later said that he is considering his position on large capacity gun magazines, which he hinted could have been used in the shooting one week ago and that several lives could have been saved had they been regulated.