The Benin international has been heavily involved with the club's community programme since moving to Hillsborough in 2011 and last year donated £5,000 to help a local school serving children with special needs buy a computer system.
Johnson, who saw off competition from MK Dons goalkeeper David Martin and Leyton Orient defender Elliot Omozusi, said: "I think (helping the community) is very important. It is part of the job. We play football, we are very happy, football gives us a lot and we have a chance to do a sport we enjoy.
"Sometimes you have to think about other people and try to help people who need it. Sometimes it is not only about money, it is just a smile, you go to see people and try to make their lives a bit easier.
"I love it. It's like when fans ask me for pictures or autographs, some people are shy but I don't think they have to be shy. We are paid for that. It is not only 90 minutes on a Saturday, it is a full week and we are well paid to do that."