Rizwan Javed, a worker on Transport for London’s Elizabeth line has saved 29 people from taking their own lives since 2015.
Now artist Jack Dickson has captured Mr Javed’s “humility and dignity” after they were brought together as part of BBC One’s Extraordinary Portraits programme.
Presented by Bill Bailey, it pairs artists with people who have powerful stories.
Mr Javed said taking part was “emotional and rewarding” – and Dickson described his subject’s actions as “awe-inspiring”.
The pair did not meet until the cameras started rolling and Dickson began observing the transport worker to get a sense of who he was, ahead of beginning the painting.
“I had no idea what his story was or anything.
“It was a complete surprise. Everything they caught on camera was a genuine reaction.”
Mr Javed said he was “really nervous” ahead of his first meeting with the painter.
“I remember my palms were sweating and I was like, ‘I’m going to meet this guy, he’s going to do a portrait of me, what’s he going to be like?
“I have to spend x amount of time with him, am I going to want to share my story?’”
To get a sense of how he interacts with the commuters, Dickson watched Mr Javed at work.
“I like to think I am a people person.
“I will engage in conversation. If I feel like someone’s facial expressions are not right, or the piece of clothing they’re wearing doesn’t fit in line with weather conditions, or they’re hanging around the area for a while, I’ll just approach them.
“There’s so much wrong going out there in the world, we all have to do our little bit to make a difference.”