First, Erin Callan Montella went quietly, but now she's come back swinging.

Callan Montella spoke Wednesday on CNBC's "Closing Bell," and said her decision to publish an autobiography was motivated by a need to explain herself in the wake of her own personal failures and after Lehman Brothers' collapse. "I wanted to take accountability for my own actions," she told CNBC. "Nobody wanted me to fail. There was no incentive to have me fail." "Full Circle," the self-published book from Callan Montella, ex-chief financial officer of Lehman, represents one of the more candid assessments of the bank's struggle and failure in the 2008 global financial crisis. But the book also delves deeply into her own failings and broken relationships, while showcasing the pain felt by the executive once viewed as the most important woman on Wall Street. On "Closing Bell," Callan Montella stopped short of saying her career was ended by gender issues on Wall Street. Callan Montella (who assumed the second surname after marrying her husband, Anthony Montella) talks about the day she was fired from the bank as it tried to beat back waves of liquidity pressures and press leaks that would undo not just her Wall Street career, but Lehman itself. "I know I started to cry," Callan Montella wrote, adding, "I'd given Lehman every ounce of myself for 13 years: all of my focus, energy and passion."

Erin Callan Source: CNBC

Callan Montella joined Lehman Brothers in her late 20s in 1995, not long after the bank had been carved out of credit card company American Express. She quickly climbed the ranks, impressed clients and by 2007 was promoted to the role of chief financial officer — a position that would ultimately pit her against famed short-seller David Einhorn. An "antagonistic" call with the Greenlight Capital manager preceded his Lehman short call, and, in Callan Montella's opinion, became portrayed as a battle between individuals. "I truly felt I had lost all sense of control over myself and how I was portrayed," she wrote. "Our one conversation had snowballed into a complete disaster of unforeseen consequences. And now I was paying the price in the media for decisions I wasn't making." Callan Montella's personal anecdotes are especially revealing — from early failed attempts to conceive a child, to her fear of humiliating herself at one of the country's finest golf courses with Och-Ziff executives Dan Och and Dave Windreich. The contrast between Callan Montella's frankness and other veterans of Lehman is stark. Her book comes less than a year after her former boss, ex-Lehman CEO Dick Fuld, spoke at a New York banking industry conference and continued to present a feisty defense of his tenure atop the defunct bank. Unlike Callan Montella, Fuld seemed intent in May 2015 on fighting battles he had lost years before. Speaking at the Marcum MicroCap Conference last year, the former CEO still insisted Lehman was "not a bankrupt company" in fall 2008. Nearly eight years after Lehman's collapse, Callan Montella said on "Closing Bell" that she has not spoken with Fuld recently, and that she doesn't hold any ill will toward Einhorn for his attack on Lehman in 2008. "These are not important issues in my life," she said. Read MoreInside Erin Callan's Hamptons hideaway