Officer Calender is in his 39th year in law enforcement. He began his career with the Dallas County Sheriff Department. After several years he went to work for the Greenville Police Department as a Patrol Officer. In 2003 Officer Calender was assigned to the Support Services Division as a School Resource Officer and was assigned to all the Greenville ISD Campuses. Officer Calender retired from the Greenville Police Department in 2017.
In 2017 he went to work for the Terrell ISD Police Department as a School Resource Officer, assigned to the Head Start and elementary campuses. This is where he got the Nickname OC. Because the little kids could not say Officer Calender so they asked if they could call him OC for short. Officer Calender left Terrell in 2022 and began working for the Quinlan ISD Police Department.
Officer Calender is married with two children and six grandchildren.