The daughter of actors Alan Vint and Susan Mullen, she began working as an actress at an early age and was a SAG member by time she was four years old, although, Vint-Castro's first formal acting job was at nine months old in a commercial.
After the new Stargate series was announced at San Diego Comic-Con in July, 2017, Mercedes asked Vint-Castro to make a cameo appearance as an older Catherine Langford.
[4][5] Vint-Castro, who is credited under the name Kelly Boone in the film Reversal, portrays the secret girlfriend of high school wrestler Leo Leone, played by Danny Mousetis.
The 2001 independent family feature is directed by Alan Vint, (Vint-Castro's father) and written by actor Jimi Petulla, who based the script on his own experiences as a high school wrestler.
Her father Alan Vint acted in such films as Panic in Needle Park and The Deadly Tower and in a variety of TV Series such as, Hawaii Five-0, Bonanza, and Baretta.