Calderon was born in a Spanish town outside Madrid called Alcobendas, and he has been living in the United States since 2008.[9][4]
Calderon criticized lawmakers for failing to enact sensible gun laws as well as screenings to keep mentally ill people from being able to buy "military grade weapons",[8] and he criticized the National Rifle Association (NRA)[6] and their spokesperson Dana Loesch for encouraging gun proliferation[10] as well as politicians funded by the NRA. He said that student voices were not being taken seriously enough.[11] He described a proposal of arming teachers to further school safety as a "terrible idea", explaining that teachers were never meant to carry lethal weapons.[12][13] He views his advocacy as more than merely protecting Parkland students but as an effort to save human lives in general.[14] He believes that it is up to the electorate to vote out politicians who support lax gun regulations and the NRA.[7]
During the school shooting, he was locked in a closet with fellow students for three to four hours.[8][11]
I was in a closet, locked for four hours with people who I would consider almost family, crying and weeping on me, begging for their lives. I understand what it’s like to text my parents, ‘Goodbye, I might never ever, ever get to see you again. I love you.’ I understand what it’s like to fear for your life.
^ abcStaff (February 22, 2018). "Así es Alfonso Calderón, el joven español que sobrevivió al tiroteo y lucha por el control de armas". 20minutos (Spanish news). Retrieved March 12, 2018. ...Nació en Alcobendas, una localidad cercana a Madrid, hace dieciséis años, aunque lleva ya diez viviendo en Estados Unidos (from Google translate:) He was born in Alcobendas, a town near Madrid, sixteen years ago, although he has already been living in the United States for ten years....
^ abcTaylor Swack (February 21, 2018). "Who is Alfonso Calderon? Florida shooting survivor gives passionate speech in Tallahassee". Newsweek. Retrieved March 12, 2018. ...The 16-year-old junior attends Marjory Stoneman Douglas High School in Parkland, where 17 people died in a February 14 massacre. He gave a roughly six-minute speech at the Wednesday rally in Tallahassee ...
^ abcStaff (19 February 2018). "Gun control: 'Kids are being slaughtered senselessly'". Radio New Zealand. Retrieved March 12, 2018. ...founding members Alfonso Calderon survived the massacre by hiding in a closet with classmates for three hours.... they didn't care enough to pass screenings strict enough so that someone who is clearly mentally ill ... a military grade weapon ... Calderon said. ...
^ abJessica McBride (February 21, 2018). "Alfonso Calderon: 5 Fast Facts You Need to Know". Heavy.com. Retrieved March 12, 2018. ...Calderon ... invited to a CNN Town Hall on February 21 to address their calls for change, including to gun laws ... also in Tallahassee, Florida ... lobbied the Florida Legislature for change.... People Praised the Eloquence of Calderon ...
^Leinz Vales (February 22, 2018). "Teachers are not meant to carry AR-15s, student survivor says". CNN. Retrieved March 12, 2018. ...(CNN)Florida school shooting survivor Alfonso Calderon said Wednesday that President Donald Trump's suggestion of arming teachers and school staff with weapons to enhance school safety was a "terrible idea."...
^Tampa Bay Times, Bill Maxwell, March 1, 2018, Maxwell: Reasonable people do not want teachers to be armed, Retrieved March 22, 2018, "... I watched 16-year-old Alfonso Calderon ... speak with CNN’s Don Lemon about President Donald Trump’s proposal to arm teachers. This young man’s wisdom, his clear understanding of the essential role of teachers, should shame Trump and other Republicans beholden to the NRA...."
^College Media Network, Abby Goss, February 22, 2018, Florida Students Swarm the Capitol and Demand Reform, Retrieved March 22, 2018, "...Many students such as Alfonso, feel as if they are not taken seriously and that they do not understand the issue ... want reform...."