David Sheff

Steve Carell

Nicholas "Nic" Sheff

Timothée Chalamet

Karen Barbour

Maura Tierney

Vicki

Amy Ryan

Jasper Sheff

Christian Convery

Dr. Brown

Timothy Hutton

Daisy Sheff

Oakley Bull

Lauren

Kaitlyn Dever

Spencer

Andre Royo

Julia

Stefanie Scott

Rose

LisaGay Hamilton

Gack

Julian Works

12-Year-Old Nic Sheff

Jack Dylan Grazer

8-Year-Old Nic Sheff

Zachary Rifkin

5-Year-Old Nic Sheff

Kue Lawrence

Diane

Amy Forsyth

Destiny

Ricky Low

Vince

Carlton Wilborn

Annie Goldblum

Amy Aquino

Julia's Mother

Marypat Farrell

Kid

Mandeiya Flory

Kid

Brandon James Cienfuegos

Kid

Cheska Corona

Speaker @ 12 Step Meeting

Anastasia Leddick

Wedding Guest

Justin Townes Earle

Flight Attendant

Martha T. Newman

Father @ Graduation

Seann Gallagher

Nurse @ Bellevue

Minerva García

Airline Attendant

Nikki Snipper

Meeting Leader

Tom Beyer

Minister

Edward Fletcher

Rocker (uncredited)

David Mendenhall

Principal @ Graduation

Brooklin Thacher

EMT

Sasha Kelly Jackson

Big Guy

Frederick Lawrence