McCaw, in a statement released by Baylor early Monday night, said "after much reflection and prayer, I have decided that a change in athletics department leadership is in Baylor University's best interest in order to promote the unity, healing and restoration that must occur in order to move forward."
McCaw, who had served as Baylor's athletic director since 2003, was sanctioned and put on probation Thursday following the school's investigation into its mishandling of sexual assault cases.
"I have always sought to put the university's needs ahead of my own," McCaw said in the statement. "My time at Baylor has been an incredible journey filled with some of the most remarkable people I have ever known. I am grateful to Baylor Nation for its support and dedication, and to all who have done so much to advance the athletics program."
The school's board of regents had disciplined McCaw as part of its response to the findings of the independent Pepper Hamilton investigation. But McCaw was being retained to help implement the recommendations that came with that report and restore accountability and oversight to the athletic department.
Instead, McCaw elected to resign.
"We understand and accept this difficult decision by Ian McCaw to resign as athletic director and are grateful for his service to Baylor University," the board of regents said in a statement. "We also appreciate Ian's commitment and involvement in bringing a person of integrity such as Jim Grobe to the University before making this decision."
Earlier Monday, Baylor said it had hired Grobe on an interim basis to replace Art Briles.
Grobe, 64, takes over a Baylor program that has been rocked by allegations of sexual assault and other violence involving several players. Last week, Baylor's board of regents suspended Briles with intent to terminateand stripped chancellor Kenneth Starr of his title of university president.
"Jim Grobe is the right leader at this time to move Baylor University and the football program forward," McCaw said in a statement earlier Monday.
"He has successfully led two FBS programs during his career," McCaw said in the statement. "Coach Grobe enjoys an impeccable reputation within the intercollegiate athletics community and is a man of great integrity and faith."
According to sources, the Bears also considered formerSan Francisco 49erscoach Mike Singletary, who is a former Baylor All-American, and current defensive coordinator Phil Bennett for the job before settling on Grobe, who last coached in college in 2013.
"It is an honor for me to have the opportunity to join the Baylor football program during this important time," Grobe said in the statement. "I am looking forward to getting to know and working with the coaches and players in the coming days, and I have great respect for Baylor as an institution and its long-standing heritage.
"As a coach, winning is important. At the same time, I want to assure the Baylor family that every decision we will make in this football program will be made with Baylor University, her students and our student-athletes in mind."
Grobe, a native of Huntington, West Virginia, coached at Ohio from 1995 to 2000 and Wake Forest from 2001 to 2013. He had a 77-82 record in 13 seasons with the Demon Deacons, and his teams played in five bowl games. In 2006, Grobe guided Wake Forest to an 11-3 record and an unlikely ACC championship.
Grobe resigned as Wake Forest's coach after a 4-8 finish in 2013, his fifth consecutive losing season.
Briles, 60, had eight years left on a contract that paid him nearly $6 million per season, which made him the Big 12's highest-paid coach. After inheriting a program that had endured 12 consecutive losing seasons before Briles was hired, he directed the Bears to at least a share of back-to-back Big 12 titles in 2013 and 2014.
Briles had a 65-37 record in eight seasons at Baylor, and his teams won 10 or more games in four of the past five seasons and played six consecutive bowl games.
In the fall of 2015, Baylor hired Philadelphia law firm Pepper Hamilton to review its past treatment of sexual assault claims. ESPN's Outside the Lines reported last week that some Baylor officials, including coaches, knew about incidents of sexual assault, domestic violence and other acts of violence involving football players, but most players didn't miss playing time as punishment.
In its report, Pepper Hamilton wrote: "There are significant concerns about the tone and culture within Baylor's football program as it relates to accountability for all forms of student athlete misconduct."
Two Baylor players accused of sexual assault were recruited by Briles after they were dismissed from their previous schools for off-field problems. In August 2015, former Baylor football player Sam Ukwuachu was sentenced to 180 days in jail after he was convicted of sexually assaulting a women's soccer player. Briles was criticized for accepting Ukwuachu as a transfer student after then-Boise State coach Chris Petersen dismissed him from the team for off-field issues. Ukwuachu's former girlfriend testified at his trial that he had struck and choked her when he attended Boise State.
Then, in April, former Bears star defensive end Shawn Oakman was arrested on a charge of sexual assault. A Baylor graduate student told Waco, Texas, police that Oakman "forcibly removed" her clothes, forced her onto his bed and then sexually assaulted her on April 3, according to an arrest warrant obtained by ESPN.
Oakman, the school's all-time sacks leader who wasn't selected in last month's NFL draft, told police he had consensual sex with the woman. Oakman was dismissed from Penn State after he allegedly grabbed the wrist of a female store clerk.
Information from ESPN's Max Olson, Adam Schefter and Mark Schlabach was used in this report.
Jim Grobe tabbed as Interim coach at Baylor
Mark Schlabach reacts to Baylor hiring former Wake Forest coach Jim Grobe as interim head coach and what could happen to the rest of the Bears' coaching staff.