Here is a complete list, both chronological and alphabetical of the 33 people to hold the position of head writer for "Days of Our Lives." Below that is a list of the head writers based on their amount of tenure with the show.

CHRONOLOGICAL

Writer(s)...........................................Start Date-End Date.........Episodes (Total)
Peggy Phillips & Kenneth Rosen...........11/8/65-12/31/65.............0001-0038      (38)
Peggy Phillips......................................1/3/66-7/4/66..................0039-0167    (129)
William J. Bell.......................................7/5/66-5/6/75.................0168-2378   (2211)
Pat Falken Smith..................................5/7/75-4/19/77...............2379-2880     (502)
Ann Marcus..........................................4/20/77-2/26/79.............2881-3362     (482)
Elizabeth Harrower................................2/27/79-3/14/80.............3363-3633     (271)
Ruth Brooks Flippen..............................3/17/80-4/18/80.............3634-3658       (25)
Nina Laemmle.......................................4/21/80-10/9/80.............3659-3782     (124)
Michelle Poteet-Lisanti...........................10/10/80-10/17/80 ........3783-3788        (6)
Gary Tomlin & Michelle Poteet-Lisanti.....10/20/80-10/20/81.........3789-4044     (256)
Pat Falken Smith..................................10/21/81-4/16/82...........4045-4170     (126)
Margaret DePriest & Sheri Anderson.......4/19/82-9/21/84............4171-4802     (632)
Margaret DePriest, Sheri Anderson & Thom Racina..9/24/84-10/25/84.........4803-4826      (24)
Sheri Anderson & Thom Racina...............10/26/84-11/30/84........4827-4852      (26)
Sheri Anderson, Thom Racina & Leah Laiman......12/3/84-11/10/86..........4853-5352     (500)
Thom Racina & Leah Laiman..................11/11/86-11/18/86........5353-5358         (6)
Leah Laiman.........................................11/19/86-3/14/89..........5359-5955     (597)
Anne Howard Bailey..............................3/15/89-1/19/90............5956-6175     (220)
Richard J. Allen & Anne Schoettle..........1/22/90-6/18/91............6176-6536     (361)
Gene Palumbo......................................6/19/91-1/30/92............6537-6694     (158)
Richard J. Allen & Beth Milstein.............1/31/92-6/11/92............6695-6789       (95)
Sheri Anderson.....................................6/12/92-7/9/92.............6790-6807       (18)
Sheri Anderson & Gene Palumbo...........7/10/92-8/6/92..............6808-6827      (20)
Sheri Anderson.....................................8/7/92-12/18/92............6828-6922      (95)
Sheri Anderson & James E. Reilly..........12/21/92-4/28/93..........6923-7012      (90)
James E. Reilly.....................................4/29/93-11/20/97.........7013-8172    (1160)
James E. Reilly & Sally Sussman Morina............11/21/97-12/23/97..........8173-8194      (22)
Sally Sussman Morina.........................12/24/97-10/14/99...........8195-8651    (457)
Lorraine Broderick..................................10/15/99-11/10/99.......8652-8670      (19)
Tom Langan..........................................11/11/99-3/28/02.........8671-9272     (602)
Peter Brash & Paula Cwikly....................3/29/02-3/6/03............9273-9511     (239)
Dena Higley...........................................3/7/03-8/8/03.............9512-9617     (106)
Dena Higley & James E. Reilly................8/11/03-8/15/03..........9618-9622      (5)
James E. Reilly......................................8/18/03-10/4/06..........9623-10414   (792)
Hogan Sheffer........................................10/5/06-1/24/08.........10415-10747   (333)
Dena Higley...........................................1/25/08*-8/25/11.......10748-11659   (912)
Marlene McPherson & Darrell Ray Thomas, Jr.......8/26/11-8/16/12.........11660-11898   (239)
Gary Tomlin & Christopher Whitesell....8/17/12-8/18/15..........11899-12656   (758)
Josh Griffith & Dena Higley...................8/19/15-2/19/16..........12657-12785   (129)
Josh Griffith, Dena Higley & Beth Milstein..2/22/16-9/2/16......12786-12912   (127)
Dena Higley & Ryan Quan.....................9/6/16-7/18/17..........12913-13131   (219)
Ron Carlivati..........................................7/19/17-Present........13132-Present  (+)

*Higley's start date is listed as 1/25/08, although she was not credited on-screen until 4/23/08.
**Exact switchover dates from 1989-1997 are unknown due to many episodes airing without credits during those years. The start dates for all writers from 1989-1997 are for the first episode credited to them on screen. Here is a list of the 19 "uncredited episodes" (which I gave credit above as the previous writer's end date in all cases): 3/13-3/14/89; 1/18-1/19/90; 6/14-6/18/91; 1/30/92; 6/9-6/11/92; 7/9/92; 12/16-12/18/92; 4/26-4/28/93; 11/20/97.
(Example: 3/13/89-3/14/89 means Leah Laiman was last credited on screen on 3/10/89; no credits were run from 3/13/89-3/14/89; and Anne Howard Bailey was first credited on screen on 3/15/89; Laiman gets the "uncredited episodes" added to her official count and her end date is listed as 3/14/89 but Bailey may have actually written one or both of those 2 "uncredited" episodes).

ALPHABETICAL

Richard J. Allen.....................1990-1991;1992
Sheri Anderson.....................1982-1986;1992-1993
Anne Howard Bailey..............1989-1990
William J. Bell........................1966-1975
Peter Brash...........................2002-2003
Lorraine Broderick.................1999
Ron Carlivati..........................2017-Present
Paula Cwikly.........................2002-2003
Margaret DePriest.................1982-1984
Ruth Brooks Flippen.............1980
Josh Griffith...........................2015-2016
Elizabeth Harrower................1979-1980
Dena Higley..........................2003; 2008-2011; 2015-2017
Nina Laemmle......................1980
Leah Laiman.........................1984-1989
Tom Langan..........................1999-2002
Ann Marcus...........................1977-1979
Marlene McPherson...............2011-2012
Beth Milstein..........................1992, 2016
Sally Sussman Morina...........1997-1999
Gene Palumbo......................1991-1992;1992
Peggy Phillips.......................1965-1966
Michelle Poteet-Lisanti..........1980-1981
Ryan Quan............................2016-2017
Thom Racina........................1984-1986
James E. Reilly.....................1992-1998;2003-2006
Kenneth Rosen.....................1965
Anne Schoettle.....................1990-1991
Hogan Sheffer.......................2006-2008
Pat Falken Smith..................1975-1977;1981-1982
Darrell Ray Thomas, Jr.........2011-2012
Gary Tomlin.........................1980-1981; 2012-2015
Christopher Whitesell............2012-2015

LONGEST-TO-SHORTEST TENURE

William J. Bell..........................8 Years, 10 Months (1966-1975)
James E. Reilly........................8 Years, 3 Months (1992-1998,2003-2006)
Dena Higley.............................5 Years, 11 Months (2003, 2008-2011, 2015-2017)
Sheri Anderson........................5 Years, 7 Months (1982-1986,1992-1993)
Leah Laiman............................4 Years, 3 Months (1984-1989)
Gary Tomlin.............................4 Years (1980-1981, 2012-2015)
Christopher Whitesell...............3 Years (2012-2015)
Margaret DePriest....................2 Years, 6 Months (1982-1984)
Tom Langan.............................2 Years, 5 Months (1999-2002)
Pat Falken Smith......................2 Years, 5 Months (1975-1977,1981-1982)
Thom Racina............................2 Years, 2 Months (1984-1986)
Ron Carlivati.............................2 Years+ (2017-Present)
Ann Marcus..............................1 Year, 10 Months (1977-1979)
Sally Sussman Morina.............1 Year, 10 Months (1997-1999)
Richard J. Allen........................1 Year, 9 Months (1990-1991,1992)
Anne Schoettle.........................1 Year, 5 Months (1990-1991)
Hogan Sheffer..........................1 Year, 4 Months (2006-2008)
Elizabeth Harrower...................1 Year, 1 Month (1979-1980)
Josh Griffith...............................1 Year (2015-2016)
Michelle Poteet-Lisanti..............1 Year (1980-1981)
Marlene McPherson..................1 Year (2011-2012)
Darrell Ray Thomas, Jr.............1 Year (2011-2012)
Peter Brash...............................11 Months (2002-2003)
Paula Cwikly..............................11 Months (2002-2003)
Ryan Quan.................................11 Months (2016-2017) 
Anne Howard Bailey..................10 Months (1989-1990)
Beth Milstein...............................10 Months (1992, 2016)
Gene Palumbo............................8 Months (1991-1992,1992)
Peggy Phillips..............................8 Months (1965-1966)
Nina Laemmle.............................6 Months (1980)
Kenneth Rosen............................2 Months (1965)
Lorraine Broderick.......................1 Month (1999)
Ruth Brooks Flippen....................1 Month (1980)

*: As of 7/31/19.