Conlon was born in 1980 or 1981. At the early age of 15, Conlon showed interest in cooking and gained knowledge of classic sensibilities. Conlon graduated from Greater Lowell Technical High School in 1999.
He became the youngest chef to win the AAA 4 Diamond Award for Augustine’s at Fredericksburg Square in Virginia.
Conlon and his business partner, Adrienne Lo, founded X-marx, an underground supper club in Chicago that served seven to 12 courses, three to four times per week, without repeating dishes and no repetition of a dish to serve.
In November 2012, Conlon and Lo opened their own fine-dining restaurant, Fat Rice, named after the home-style arroz gordo in Logan Square, Chicago. Conlon was the head chef of Fat Rice. After interviewing previous workers of Fat Rice The New York Times reported in 2020 that the employees largely portrayed Conlon as "an extreme example of a restaurant-business archetype: a tantrum-prone chef who rules by fear and bullying". He published a letter of regret, saying, "I have hurt and let down many people. I hear the criticism of my character and behavior. As process and reflect, I'm realizing who I am, who I've become, and how I need to change. I am taking this time to learn and to grow so that I may be better for the people I have damaged."