An AWS IAM developer manages access control by creating and implementing AWS Identity and Access Management (IAM) policies. They define who is authenticated and authorized to use AWS resources. Their tasks involve creating users, groups, and roles, and specifying their access permissions to AWS services. They also manage AWS security credentials like access keys, password policies, and multi-factor authentication. Moreover, they monitor and troubleshoot security-related issues using AWS CloudTrail. Essentially, they ensure the right individuals have appropriate access to specific AWS resources, thus maintaining the organization's security posture.