The Park Keeper is a minor character portrayed by Steve Nicolson in the film Mary Poppins Returns as a worker at the park who doesn't want anyone walking on the "Keep off the Grass" areas.
The Park Keeper, as his name suggests, is a guard who warns guests to stay off the grass. Every time whenever someone runs on the grass, he constantly tells the person to stay off, warning guests in a strict behavior.
Behind the scenes
Steve Nicolson makes his Disney feature film debut as the Park Keeper in the film Mary Poppins Returns. As an actor, Steve Nicolson is known for his film performances in K-19: The Widowmaker (2002), Criminal (2016) and Johnny English (2003).
The Park Keeper is prominently featured as a gag character where he appears at the beginning of the film telling guests to keep off the grass. Just as John, Annabel and Georgie attempt to retrieve the kite, the park keeper notices this. Just as Jack arrives, he grabs the kite Michael used to own as a child to which Mary Poppins arrives toward the group. He later appears again during the musical number "Can You Imagine That?" where he appears as reminiscent of his real world version, only telling visitors to keep off the sea grass. During the end of the film, he does not notice the Banks children walking on the grass.