Sus papeles más conocidos son el detective privado Lucas Douglas en House, Gordon Page en The Resident, el homicida adicto a la metanfetamina Jake en la serie de HBO Six Feet Under y Pvt.

Personificó a Simón Marsden (Hollister), hermano de la detective Olivia Benson en la serie La Ley y el Orden: SVU.

[2]​ Weston es un amigo cercano y antiguo compañero de piso del actor Zach Braff; han compartido la pantalla en diversas películas, como Getting to Know You (1999), Garden State (2004), The Last Kiss (2006) y Wish I Was Here (2014).

[6]​ 4.5 "That's My Dog" 4.8 "Coming And Going" 4.12 "Untitled" 5.10 "All Alone" 12.22 "Twenty-One Guns" 13.1 "Bloodline" 1.12 "Cloudy...Chance of Murder" 8.3 "Remake A.K.A.

Cloudy... With a Chance of Improvement" 6.7 "His Story IV" 6.9 "My Perspective" 6.10 "My Therapeutic Month" 6.12 "My Fishbowl" 8.13 "Loophole" 8.16 "Philadelphia" 8.19 "Florida" 8.22 "Screwed" 13.16 "Child’s Welfare" 21.6 "Murdered at a Bad Address" 5.2 "Not Cancer" 5.3 "Adverse Events" 5.5 "Lucky Thirteen" 6.7 "Known Unknowns" 6.8 "Teamwork" 6.9 "Ignorance Is Bliss" 6.12 "Remorse" (cameo) 6.13 "Moving the Chains" 6.14 "5 to 9" 6.18 "Knight Fall" Based on the 1977 novel by Robin Cook 1.8 "Insomnia" 1.9 "Untethered" 1.10 "Surrender" 3.16 "For All You Know" 3.24 "A Controlled Descent"