John G. STRAUB named his first son, William John, so it's very likely our subject's middle name was John.

William appears to have been married at least once, if not twice, and to have been either widowed or divorced each time.

1.  Marriage Record:

2.  1870 Census Every-Name-Index/Images (online at Ancestry.com):  can't find William or his brother, John G. STRAUB, and they should be in the U.S.

3.  1880 Census Every-Name-Index/Images (online at Ancestry.com):  can't find William or his brother, John G. STRAUB, and they should be in the U.S.

4.  1890 Census:  the 1890 Census Population Schedules were destroyed.

5.  1900 Census Every-Name-Index/Images (online at Ancestry.com, Image #22 of 25):  1700 W Main Street, Louisville City (Ward 11), Magisterial District No. 8, Jefferson Co., KY, Roll T623_532 (Book 1), p. 94B, SN 11, SD 5, ED 108, enumerated 11 Jun 1900, official enumeration date 1 Jun 1900 (extracted by Diana Gale Matthiesen):¤•

1900:  for an explanation of the column headings, please see What the Numbers in the Federal Census Mean (missing columns contained no data).

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

19

20

22

23

24

25

27

*

1700

218

243

Herbold Philip

Head

W

M

Dec 1866

33

M

1

KY

Ger

Ger

Saloon

0

Y

Y

Y

R

H

_______ Maggie

Wife

W

F

May 1876

24

M

1

1

1

KY

KY

KY

Keeping House

Y

Y

Y

_______ Helen

Dau

W

F

Jan 1900

4/12

S

KY

KY

KY

Straub William

Boarder

W

M

Sep 1869

30

S

KY

Ger

Ger

Millwright

0

Y

Y

Y

*W Main Street

This appears to be our subject (I can't find anyone who is a closer match).  William's brother, John G. STRAUB, is also in Louisville.

6.  1910 Census Index/Images (online at Ancestry.com, Image #7 of 7):  Cheswick Borough, Allegheny Co., PA, Roll 1297 (Book 2), p. 251A, SN 4A, SD 23, ED 237, enumerated 18 Apr 1910, official enumeration date 15 Apr 1910 (extracted by Diana Gale Matthiesen):¤•

1910:  for an explanation of the column headings, please see What the Numbers in the Federal Census Mean (missing columns contained no data).
1	2	3	4	5	6	7	8	9	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	28
65	65	Straub J G	Head	M	W	50	M1	27	Switz (Ger)	Switz (Ger)	Switz (Ger)	1868	Na	Eng	Manager	Distillery	W	N	0	Y	Y		R	H
		[John G' wife and children]
		______ William	Brother	M	W	34	Wd		Kentucky	Switz (Ger)	Switz (Ger)			Eng	Miller	Distillery	W	N	0	Y	Y	Y

7.  1920 Census Index/Images (online at Ancestry.com, Image #11-12 of 25):  Freeport Road, Acmetonia, Harmar Twp., Allegheny Co., PA, Roll T625_1512 (Book 2), pp. 132A-132B, SN 6A-6B, SD 24, ED 125, enumerated 4 Feb 1920, official enumeration date 1 Jan 1920 (extracted by Diana Gale Matthiesen):¤•

1920:  for an explanation of the column headings, please see What the Numbers in the Federal Census Mean (missing columns contained no data).
1	2	3	4	5	6	7	9	10	11	12	17	18	19	21	22	23	24	25	26	27	28
*	X	116	128	Straub Woody	Head	R	M	W	35	M	Y	Y	KY	KY		KY		Y	Confectionary	Owner (???)	W
[next page]
				Straub William	Bachelor		M	W	50	S	Y	Y	KY	Switz	Ger	Switz	Ger	Y	Retired
*Freeport Road

Woody Preston STRAUB is William's nephew, son of his brother, John G. STRAUB.

8.  1930 Census Index/Images (online at Ancestry.com, Image #19 of 35):  412 East Market Street, Louisville City (Ward 4, Block 711), Magisterial District 6, Jefferson Co., KY, Roll 755 (Book 1), p. 10A, SN 10A, ED 56-53, SD 5, enumerated 7 Apr 1930, official enumeration date 1 Apr 1930 (extracted by Diana Gale Matthiesen):¤•

1930:  for an explanation of the column headings, please see What the Numbers in the Federal Census Mean (missing columns contained no data).
1	2	3	4	5	6	11	12	13	14	16	17	18	19	20	24	25	26	27	28	29	30
*	412	133	239	Straub William J	Lodger	M	W	60	D	N	Y	KY	SWI	SWI	Y	millwright	Body Co	W	N	23	N
*East Market Street

One of 34 men living in a hotel.