leading role
leading part

He was one of the real property commissioners in 1828, and took a leading part.

For the rest of his life he took a leading part in county affairs.

Thus he played a leading part in Germany's musical life.

So the position, on his own evidence, was that he took a leading part in the planning of the murder.

He played a leading part in Whig politics until the 1820s.

MacAlister took a leading part in the university business of the country.

This organization was a leading part of the economy of its home country.

He also played a leading part in the passing of the bill on elementary education.

Ferguson then took a leading part in organizing the rising of 1685.

He took a leading part in the revival of Irish letters.