This is something of a vague question so I do not know if this answer is what you are looking for. However...
One way to characterize the reforms of this period is to say that they were driven by people from the growing middle class. Many of these people were inspired by the religious fervor of the Second Great Awakening. During this time period, the middle class was growing. This gave more people some amount of leisure time. Many of them (especially women) were inspired by the religious revivals to try to perfect their society.
This meant that the reforms were typically driven by individuals. People like Dorothea Dix and Horace Mann went on largely personal crusades to fix problems that they saw in their society. The reforms were generally not driven by the government or by major organizations but were instead the work of individuals.
So, one way to answer this question is to say that the reforms were the work of individuals from the middle class who were (often inspired by religion) determined to make changes in their society.