The defender has been one of Everton's most consistent performers and the Republic of Ireland captain believes that the Toffees are "reaping the rewards"
The Donegal native has been ever-present in defence for Everton under Roberto Martinez, contributing five goals in 19 league appearances, and Keane says that the 25-year-old has raised his game during the new campaign.
"Seamus is a terrific player and Everton are reaping the rewards," Keane told the Irish Independent. "He was doing very well anyway, but this season he's stepped up even more."
The LA Galaxy striker has played alongside Coleman at international level for the Republic of Ireland and says that the former Sligo Rovers full back possesses qualities that are desirable for any team.
"For someone who is a right-back, he's got everything," added Keane. "You couldn't wish for someone better because he's got so much energy.
"He loves to get forward and create chances and he's very hard to beat as well."
Meanwhile, Keane is nearing recovery after undergoing surgery on his ankle in November and the 33-year-old revealed that he would be running again "within 10 days."
"I've had three weeks of rehab since the operation on my Achilles and I'll be back running within 10 days," said Keane.
"I'll certainly keep the Achilles a lot stronger, way stronger than before. I've been doing a lot of work in the swimming pool and in the gym and it feels very good.
"Already, I feel a huge benefit. So far, so good."