She was a member of the England teams that won bronze medals at the 2006 and 2010 Commonwealth Games and at the 2011 World Netball Championships.

Along with Abby Teare, Chioma Ezeogu and Sonia Mkoloma, she was a member of the Hurricanes team that lost to London Tornadoes in the 2003 Super Cup final.

Brownfield was the top scorer in the grand final when Mavericks won their first Netball Superleague title in the 2007–08 after defeating Loughborough Lightning by 43–39.

[13][14] Brownfield was captain when Mavericks' won their second Netball Superleague title in 2011 after defeating Surrey Storm by 57–46 in the grand final.

[18][19] Brownfield was a member of the England teams that won bronze medals at the 2006 and 2010 Commonwealth Games and at the 2011 World Netball Championships.