It was his first post since he received a worldwide backlash for a video he posted showing the body of an apparent suicide victim in Japan.
In his seven-minute comeback video, Paul meets activists and a suicide survivor, while pledging to donate $1m (£700,000) to prevention groups.
It has received a largely positive response from his young fans online.
The controversial video was posted on 31 December, and showed Paul and his friends during a trip to Japan discovering the body of a man in the Aokigahara forest at the base of Mount Fuji, known to be a frequent site of suicides.
The group appeared to be shocked at their find, but also made jokes. The clip was labelled "disrespectful" and "disgusting" by users online, who accused the YouTube star of trivialising mental illness.
The video was viewed millions of times before its removal. He later apologised and admitted it had been "misguided".
In response, Paul's channels were removed from YouTube's Google Preferred programme, where brands sell ads on the platform's top 5% of content creators.
YouTube also said it had put on hold original projects with the US vlogger. A petition for him to delete his account was signed hundreds of thousands of times.
In the new video, Suicide: Be Here Tomorrow, Paul addresses the controversy and admits he had let people down.
"It's time to learn from the past as I get better and grow as a human being," he says.
He says part of the problem was his "ignorance on the subject", revealing he did not know anyone personally who had died from suicide.
He also speaks to Kevin Hines, who survived a suicide attempt from San Francisco's Golden Gate Bridge aged only 19.
In the video he also shares advice with his fan base about steps they can take to help prevent suicide.
He and his brother Jake Paul are now two of YouTube's most influential users, after initially finding fame on short-form video app Vine.
They are known for their high-energy videos and shocking pranks, but now have lucrative endorsement and merchandise deals away from vlogging.
The pair, aged 20 and 22, have their own channels with millions of subscribers, many of which are teenagers or younger.
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