The former Hoops midfielder had reportedly held talks with the incoming Celtic boss over the possibility of reuniting in a Parkhead coaching capacity, the pair having worked together previously at Bournemouth.
Grant stepped down as Alloa boss last month after the Wasps were relegated to League One, but the 55-year-old has made a swift return to management after taking up his new role at East End Park.
He refused to confirm whether any discussions had taken place with Howe, who is expected to be appointed at Celtic next week.
"Eddie was a young player when I was at Bournemouth so there's been a lot in that but this was the only job I wanted,” Grant said.
"Out of the jobs that have been available this summer this is the one I wanted and I was offered it.
"I wanted to stay a manager, that's the biggest thing. Then it's my fault if it goes wrong.
"Sometimes when you're a number two you have opinions but as the manager the chop falls on you if you're not doing your job right.
"I was brought up a Celtic supporter, I was brought up a Celtic player.
"But I'm here and I think anybody that's worked with me knows Dunfermline will get the same commitment I gave Celtic at all times.
"Eddie's a pal of mine and that's as much as I'll say.
"This is not about Celtic, this is about Dunfermline."
Grant replaces Stevie Crawford, who resigned as Pars boss last week in the wake of the club's failure to win promotion to the Premiership through the play-offs.
Dunfermline said in a statement: "Peter recently resigned from his managerial position at Alloa Athletic, and boasts an impressive coaching and playing career."
Grant registered almost 400 Hoops appearances during his playing days - lifting two titles and three Scottish Cups - before going on to spells at Norwich, Reading and Bournemouth. He also won two caps for Scotland before moving into coaching.