AFL stars have previously lent their support to marriage equality forums around the country, and members of every AFL team signed a petition calling for same sex marriage on the International Day Against Homophobia And Transphobia earlier this year.
The AFL on Wednesday altered its official logo at league headquarters, chaging the letters "AFL" to "YES".
"I think that we are a leader (in the community), whether people like that or not, and this is an issue that means a lot to many of our players and many of my employees and a lot of people in the community", McLachlan said on Fox Footy.
"I think our position is that we need to have a strong statement, even if that is only for our staff, but I think it is broader than that".
"Beyond that, it's not to lecture".
"The AFL will keep saying no matter how many times it takes, that our game does not tolerate discrimination in any form, be that sexual identity, gender, race (or) religious views".
Replacing the usual AFL logo at the league's headquarters, the new logo bears the word "yes" instead, joining a growing number of voices urging Australians to vote "yes" on the same-sex marriage plebiscite.
The statement comes after numerous sporting organisations - including the ARU, the NRL, Cricket Australia and Football Federation Australia - declared their support for a "yes" vote in the ABS postal survey.
Folau, a devout Christian, tweeted last week: "I love and respect all people for who they are and their opinions. but personally, I will not support gay marriage".
Meanwhile Johns showed his support for the "yes" campaign with a photo on Instagram showing him locking lips with former Newcastle Knights teammate Billy Peden.